StabbinPayne
11-24-2004, 03:55 AM
So my SG has just finished up perfecting our technique on this trial (we can no longer get the mission any more, having all hit 41), and there are a few tricks that can be immensely helpful to finishing this up pretty quickly. By the end, we were finishing the final mission of the trial in ~30-45 minutes with just the 4 of us (DM/Inv scrapper, BS/Inv scrapper, Rad/Elec defender -- me, and Ill/Rad controller). Those who think controllers are useless here could not be further from wrong, once you discover the "trick" to bringing down the force field permanently, as described later on.
The keys for us finishing the trial quickly were: 1) high mag AE holds (and not for the reason you might think ;)), 2) someone with recall friend and high stealth (our controller had SS + group invis) who can move about vertically easily (our controller had hover 6 slotted for speed, which is about as fast as 0-1 slotted flight), and 3) grantable stealth (again, our controller provided this with group invis) if anyone can't become become invisible on their own (with stealth + SS, or whatever).
For us, Phanton Army and Phantasms were invaluable for drawing aggro at the Hydra (there were only 4 of us, and no one with any psi resistance :eek:), but anyone able to draw aggro and take the psi damage should do for this role. Obviously, our scrappers did the majority of the damage dealing (and doubled as the tanks against all the villains who were not doing 900+ psi damage attacks :eek:) with some help from Phantasms (and even less help from my occassional Ball Lightning/SC/TB ;)). But really any balanced team with good tanking/defense/damage should do for these roles. Our controller turned out to be the only absolutely essential component in being able to complete this trial so quickly, although other AT's with good hold powers (some ice blasters and rad defender builds come to mind) might also be able to bring down the force field (but probably without bringing as many other tools to the table as our controller did ;)).
Getting to the Mission
Anyway, so the first part is easy. Talk to Maren McGregor in Founder's Falls (a bit north of Penny Preston in the southwestern dock area) to get the first mission. THE ENTIRE TRIAL IS DONE AS A REGULAR MISSION IN A REGULAR TEAM, NOT AS A TASK FORCE. I believe you must be 38th to get the mission from her. If you want to do this a lot (we did), everyone in the team who can should get the mission. Each time you complete or fail the final part of the mission, you can come back to Maren to get a new access code for the maintenance door and try it again, until you hit SL 41, at which point she will no longer give you any missions (but you are still free to join teams with lower level heroes who have the mission).
Now you all head off to the abandoned sewers to defeat 150 Rikti. After that is done, everyone with the mission goes back to Maren to get the "real" mission. Now head to the center of the abandoned sewers, find the maintenance room access door, have someone use their access code to start the 90 minute timed mission, and let the fun begin!
Keep in mind, ALL villains in the mission will be level 42, so anyone below SL 38 is fairly useless unless they get sidekicked up. A small group of SL 38's might have a hard time finishing this in time unless they used every shortcut presented here (we never managed to finish it successfully until we hit 39, but we also didn't REALLY know what we were doing until we were nearly 40th about 5-6 attempts later; yes, you get XP REALLY fast in here :p),
Getting the Weapons
After entering the maintenance room, you run around (right or left, doesn't matter) until you get to the opening to the big main central chute area, with it's maze of downwardly spiraling catwalks (the first Rikti group should be hanging out at the lip of the chute entrance). Now your first step is to equip your group with the Rikti weapons.
Our controller was able to do this for us in about 5 minutes (after a lot of practice from our first few attempts which we failed due to time ;)) using his hover + recall ally + invis, although it was a little tricky avoiding the drones (the invis + SS really cuts down the drone aggro range, but they can still see you if you get close enough). You can tell what is in the Rikti crates BEFORE you open them by targeting them (right click a crate, or left click and move before you finish opening it). This was quite helpful to us once we discovered it, as we could quickly get everyone particle cannons and not waste time on the thermite cannons except for those without decent attacks for the tentacles (in this case, my defender and the controller).
If you don't have any means of sneaking past this part, you'll probably have to waste around 20-40 minutes fighting your way down through the Rikti groups (everything is level 42, with lots of bosses) until the 4 particle cannons have been secured.
Keep in mind the 4 thermite cannons are purely optional for your poorer damage dealers (they can use them to help out on the tentacles), whereas the particle cannons are absolutely essential (you cannot damage the hydra without them). There are 2 Hatched Krackens (monsters) on the way down, which are worth tons of XP (at level 38, the 4 of us were getting ~88k each per Kracken), and are treated in more detail in their own section below.
Clearing the Generators
After everyone has a weapon, you're ready to head to the bottom of the chute. This is easy for anyone with stealth abilities (just jump down and run to a wall when you hit the bottom, and try not to get stunned by a drone shot on the way down :p), or you can just wait for your teammate with recall friend to get down and summon everybody to a safe spot.
The layout of the bottom is simple, there is a central area with a giant eyeball (the Hydra) surrounded by tentacles (both minions, and lieutenant versions that split into 2 underling tentacles). The central area is circled around by some broken up boulderish terrain, with 4 equally spaced and partially separated areas containing 1 force field generator apiece between these rocky barriers and the walls. Each force field generator area has a group of 6-7 Rikti (mostly Chief Soldiers with a few Mentalists, Mesmerists, and Headman Gunners thrown in), with a Hatched Kraken (monster class villain) positioned somewhat nearby (although easily outside of aggro range from the generator groups if you are at all careful) at a gap in the rocky barrier, presumably guarding the way from the generator to the Hydra. Everything is level 42.
The first step is to clear the Rikti from the force field areas. This is quite easy and should only take 5-10 minutes. Our strategy was to start doing this at the same time our controller was getting us the Rikti weapons: as each scrapper got a particle cannon he would jump down and start beating up a generator group, and be eventually joined by my defender and the controller once we got our Rikti weapons, at which point a group or 2 would already be dead. This might be a bit tough with less durable (and/or lower level) scrappers than ours, but the invuln scrappers didn't have much trouble defeating groups with 6-7 +2-3 boss/lt's all by themselves (they occassionally died to bad timing and/or poor attention when Unstoppable dropped though ;)).
DO NOT DESTROY THE GENERATORS YET. If you do, more Rikti will spawn in about 1-2 minutes and repair the generator. If you were wise enough to bring a good controller along with several holds, you won't have to mess with these generators at all, saving a large amount of time later when you start working on the Hydra.
Defeating the Krackens
After the Rikti groups are gone, it's time to start putting down some Krackens. The important things to know about the Kracken are 1) it does a nasty AE foot stomp that hits everyone within 10-15 feet of it for ~800 phys damage at level 40, 2) it has a nasty AE spit attack that does ~500-600 untyped or poison/psi damage over 4-5 ticks (invuln doesn't protect from it, for sure ;)) to everyone near the target, 3) it's other attacks are run of the mill big single target physical attacks that only your tankers/scrappers should have to deal with.
Defeating these is pretty easy once you get the hang of it. We used a pretty standard pulling tactic: our scrapper would aggro one from range with TP foe (hiding behind terrain to avoid getting spit on), and run to our pull spot behind a large squarish boulder situated kind of in a "corner" of the wall near one of the generators (perhaps using TP foe reacquire aggro if it was a long pull). This allowed him to avoid getting spit on while the Kracken was closing to melee range.
Then after the Kracken was engaged with the scrappers at melee range, the controller and I would debuff the crap out of him. So, after he was inside a bunch of ugly green clouds (moving at a crawl, attacking maybe once every second or two, doing around half damage, and ~50% more susceptible to damage), me and the controller then just let the scrappers and pets hammer the crap out of him until he was down, staying well out of melee range except for the occassional ninja heal or buff right after a foot stomp. After we got good at this it would only take about 10 minutes to defeat all 4 Kracken, and a fair chunk of that time was spent waiting for Unstoppables to drop or for the Kracken to run up to our pull spot.
At ~88k XP (4 level 38 heroes) to ~55k XP (4 level 41 heroes) each per Kracken, you can level in a hurry here, so make sure you're done with any contacts and/or story/badge missions you wanted to do before spending much time down here (I missed 4 of my arcs, but I can't really complain much since playing around down here and figuring out our strategem was the most fun any of us had playing CoH in ages). We all went from 38 to 41 inside of 20 play hours while honing our technique, despite dying alot and even spending some time in level 39-40 acruing intentional debt so we could get more of the special enhancements to play with (which turned out not to be as cool as we had hoped).
Clearing the Tentacles
Okay, so now everything at the bottom should defeated except for a huge eyeball floating in an ugly green sea of sewage, surrounded by a bunch of upright tentacles waving lazily in the air. The Hydra itself has an assortment of high damage, very long range, psionic attacks. One is a big dot that does 5 tics of 90+ to an unresistant level 40, and the other is a big nuke that does about 900+ damage to an unresistant level 40. So, keeping this guy busy is one of your main priorities ;). The tentacles come in minion and lieutenant varieties; both shoot long range spit attacks for ~100 damage + 5-6 dot ticks of ~10 (I never noted the damage type, but I think our scrappers were resisting it); the lieutenant variety split into 2 underling tentacles when you defeat them.
Now, first things first, have someone occupy the Hydra (in our case this was our controllers Phantom Army and Phantasm decoys), and you will see a shimmery blue force field spring up around him (if it wasn't up already). The Hydra is immune to all damage while the force field is up.
While the Hydra is occupied, commence beating up tentacles. Our approach to this evolved from carefully (and VERY slowly) doing it at range with only myself and the controller blasting while the indestructible pets played with the Hydra, to basically everyone just free for alling tentacles until the Phantom Army was about to expire, then running behind some rocks until the controller could drop in another PA (about 10 seconds down time between PA's), and then wading back into the melee. With a perma army, or any kind of full time aggro drawing tank, the run away and regroup part could obviously be dispensed with, and everyone could quickly clear all the tentacles while the hydra was being kept busy (nearly any paired defender and tanker/scrapper duo should do for Hydra duty, or possibly any regen scrapper all by himself).
Towards the end, we were more or less only clearing a patch of tentacles (about a 1/3 arc around the Hydra) from which to stage our assault on the Hydra, and then blasting the Hydra to death from our clear patch after taking the field down permanently (see below), with me or the controller taking breaks as appropriate to heal and/or EMP/flash the tentacles and Rikti waves out of the action until the Hydra was banished, leaving us free to mop up any remaining villains at our leisure. All told, after getting the Krackens out of the way, we would generally finish the mission 10-20 minutes later.
Defeating the Hydra
Okay, so after the tentacles are out of the way, it's down to just you and the big guy, with that annoying force field in the way. This is where your holds can save you A LOT of time. For us, all it took was this: me and the controller would go stand within range of the Hydra, and do our EMP + EMP + flash, and voila the field was gone and never came back.
I have read elsewhere gravity controllers can knock down the field using singularities, but we didn't have much in the way of strong single target holds to see how effective those were (but presumably enough of them stacked together on the Hydra would eventually achieve the same result). Once you knock the field down this way, you can basically just shoot the Hydra until it's dead, leaving a few members (in our case, me or the controller) free at the key points to deal with the Rikti summonings.
Anyway, after the field is down, you can pull out your particle cannons and begin banishing the Hydra. These things have a HUGE animation time (about 20-25 seconds) during which you can do NOTHING, so be sure the hydra (and tentacles, if you left any) is occupied while you're standing there ghostbustering it's [censored]. I would estimate it takes about 25 particle cannon blasts to finish him off when you are all level 41, probably more like 45-50 shots if you are all level 38.
After The Hydra hits 50% health, he will summon in a large group of Rikti (almost all Headman Gunners, 12-15 or so of them, perhaps 3-4 per person if more are in the team?), so be sure a few folks are not stuck in the particle cannon animation to deal with these (our controller would stop shooting sometime around when the Hydra was about 55-60% health and wait for the Rikti to show up and then AE hold them all with flash + EMP).
At ~25% health, the Hydra will summon another group of Rikti, about the same as the prior one. Again, someone should not be locked into ghostbuster mode who can deal with these (like someone with a big AE hold). After these are dealt with, you can finish off the Hydra, clean up any remaining Rikti and tentacles, and the mission will be completed.
If you are unfortunate enough to not have anyone who can knock the Hydra's force field down permanently, you will have to do it the old fashioned way, which might add anywhere from 10-50 minutes to your trial time, depending on your group's level (affects how much damage you can do to the Hydra in the time the field is down, and hence how many times you will need to knock down the fields) and teamwork (affects how long it takes you to take down the field each time it goes back up).
The field is maintained by the 4 generators you cleared of Rikti earlier, and if you destroy all 4 generators simultaneously, you will get a ~1-2 minute "window" in which the Hydra is unshielded and you can damage it with the particle cannons. After that, Rikti groups will spawn at all the field generators and repair them, bringing the shield back up (at which point you may have done from 1/4 to 1/2 the Hydra's life, depending on the levels of the cannon wielders and assuming they got in about 2-3 shots each) and leaving you to bring them down all over again.
Back before we figured out how to KO the shield for good, our scrappers would "soften" all the field generators by knocking them down to 1/4 or less health without destroying them, to make it easier for us to bring all the generators down simultaneously. If you kill a generator prematurely, Rikti will gate in there and repair it a minute or so later, regardless of whether any of the other generators are down or not. We only experimented with the generators a little before we discovered our far superior strategy, so I'm not sure if there is a better way to deal with generators or not (i.e. if you leave a small team at 1 generator to keep it down permanently, will this keep the field down, or is only 1 generator required to bring the field back up?).
Completing the Mission
Sometime after you banish the Hydra and defeat all it's tentacles, and all the Rikti at the bottom (summoned or otherwise), the mission will complete. I recall at least once the mission completing before all the tentacles were dead, but I think those were only underling tentacles (not entirely sure about that), so I'm not EXACTLY sure when the mission completes after the Hydra has been banished.
Anyway, the special Hydra enhancements are awarded at the time the mission completes. BE SURE YOU HAVE OPEN SLOTS IN YOUR ENHANCEMENT INVENTORY OR YOU WILL NOT GET ONE. I would recommend keeping several open enhancement slots just before killing the Hydra until the mission completes, just in case you get a few from random kills right before the mission ends (I missed getting a few of these from bad inventory management, and/or from getting a few normal enhancements just before the mission completed). For whatever reason, the person whose mission the trial is will not get his enhancement until everyone has left the mission map.
The Rewards
Okay, so what is this Anti Proton Exposure thing you just got? Basically, all the Hydra enhancements seem to be +25% enhancements to several aspects of a power. The Anti Proton Exposure, for example should provide a 25% bonus to defense debuffs, accuracy debuffs, and endurance reduction (read the ingame info on the enhancement to see what it affects). The more useful ones I have seen are +acc/dam (for almost everyone), +heal/-end (useful for many), +acc/mez (mez is a bonus to ALL status effects except slow, highly useful for controllers obviously), +range/dam (for blasters), +accbuff/defbuff/-end (for some defenders), +accdebuff/+defdebuff/-end (for rad/kinetics), +accdebuff/+defdebuff/+acc (for dark/kinetics).
Officially, I have only tested the damage component of one of these enhancements, but it was exactly 25% at even level (all the Hydra enhanemcents are level 40) when I did, and this led me to believe what I have read elsewhere that they provide a 25% bonus to whatever their description says they affect. At level 41, I tested it again, and it provided only a 22.5% damage bonus, so these enhancements also degrade at the standard 10% per level below yours (and presumably increase by the standard 5% per level above yours). Also, I can say with authority that identical Hydra enhancements will not combine, so you can not extend their useful lifetimes via that route.
Hydra enhancements are also reputed to work if your level is within 5 levels of theirs (rather than the standard 3). But basically they provide little to no benefit over a regular +3 SO (which is +38.3%) after they become -2 (only +20% bonuses) unless it was providing at least 3 bonuses you wanted (for example, Anti Proton Exposure is the only one I will be keeping slotted after I hit 42, since it provides 3 useful bonuses in Radiation Infection).
So, they are kinda cool, but very hard to get on your own until level 39 (unless you team with higher level folks), at which point they are only useful for a couple levels unless you have one that is a 3-point (or better) match for one of your powers. Obviously, if you only like one of the bonuses these enhancements provides, you are much better off using a standard +3 SO. These enhancements could make very nice gifts to a level 35 hero who had a well matched power, however.
Possibly, more useful than the Hydra enhancements you get are all the L41-42 SO's you will get from killing all those Rikti bosses, to patch up your ailing L40 SO's until you can replace them with shiny new L45 SO's at SL42. And of course, you can't overlook the ridiculous amounts of XP you rake in from killing all those Krackens (each member of a well constructed 4-man team could easily level every 3-7 hours from SL38-SL41, depending on how quickly you can get all the tactics down pat).
The keys for us finishing the trial quickly were: 1) high mag AE holds (and not for the reason you might think ;)), 2) someone with recall friend and high stealth (our controller had SS + group invis) who can move about vertically easily (our controller had hover 6 slotted for speed, which is about as fast as 0-1 slotted flight), and 3) grantable stealth (again, our controller provided this with group invis) if anyone can't become become invisible on their own (with stealth + SS, or whatever).
For us, Phanton Army and Phantasms were invaluable for drawing aggro at the Hydra (there were only 4 of us, and no one with any psi resistance :eek:), but anyone able to draw aggro and take the psi damage should do for this role. Obviously, our scrappers did the majority of the damage dealing (and doubled as the tanks against all the villains who were not doing 900+ psi damage attacks :eek:) with some help from Phantasms (and even less help from my occassional Ball Lightning/SC/TB ;)). But really any balanced team with good tanking/defense/damage should do for these roles. Our controller turned out to be the only absolutely essential component in being able to complete this trial so quickly, although other AT's with good hold powers (some ice blasters and rad defender builds come to mind) might also be able to bring down the force field (but probably without bringing as many other tools to the table as our controller did ;)).
Getting to the Mission
Anyway, so the first part is easy. Talk to Maren McGregor in Founder's Falls (a bit north of Penny Preston in the southwestern dock area) to get the first mission. THE ENTIRE TRIAL IS DONE AS A REGULAR MISSION IN A REGULAR TEAM, NOT AS A TASK FORCE. I believe you must be 38th to get the mission from her. If you want to do this a lot (we did), everyone in the team who can should get the mission. Each time you complete or fail the final part of the mission, you can come back to Maren to get a new access code for the maintenance door and try it again, until you hit SL 41, at which point she will no longer give you any missions (but you are still free to join teams with lower level heroes who have the mission).
Now you all head off to the abandoned sewers to defeat 150 Rikti. After that is done, everyone with the mission goes back to Maren to get the "real" mission. Now head to the center of the abandoned sewers, find the maintenance room access door, have someone use their access code to start the 90 minute timed mission, and let the fun begin!
Keep in mind, ALL villains in the mission will be level 42, so anyone below SL 38 is fairly useless unless they get sidekicked up. A small group of SL 38's might have a hard time finishing this in time unless they used every shortcut presented here (we never managed to finish it successfully until we hit 39, but we also didn't REALLY know what we were doing until we were nearly 40th about 5-6 attempts later; yes, you get XP REALLY fast in here :p),
Getting the Weapons
After entering the maintenance room, you run around (right or left, doesn't matter) until you get to the opening to the big main central chute area, with it's maze of downwardly spiraling catwalks (the first Rikti group should be hanging out at the lip of the chute entrance). Now your first step is to equip your group with the Rikti weapons.
Our controller was able to do this for us in about 5 minutes (after a lot of practice from our first few attempts which we failed due to time ;)) using his hover + recall ally + invis, although it was a little tricky avoiding the drones (the invis + SS really cuts down the drone aggro range, but they can still see you if you get close enough). You can tell what is in the Rikti crates BEFORE you open them by targeting them (right click a crate, or left click and move before you finish opening it). This was quite helpful to us once we discovered it, as we could quickly get everyone particle cannons and not waste time on the thermite cannons except for those without decent attacks for the tentacles (in this case, my defender and the controller).
If you don't have any means of sneaking past this part, you'll probably have to waste around 20-40 minutes fighting your way down through the Rikti groups (everything is level 42, with lots of bosses) until the 4 particle cannons have been secured.
Keep in mind the 4 thermite cannons are purely optional for your poorer damage dealers (they can use them to help out on the tentacles), whereas the particle cannons are absolutely essential (you cannot damage the hydra without them). There are 2 Hatched Krackens (monsters) on the way down, which are worth tons of XP (at level 38, the 4 of us were getting ~88k each per Kracken), and are treated in more detail in their own section below.
Clearing the Generators
After everyone has a weapon, you're ready to head to the bottom of the chute. This is easy for anyone with stealth abilities (just jump down and run to a wall when you hit the bottom, and try not to get stunned by a drone shot on the way down :p), or you can just wait for your teammate with recall friend to get down and summon everybody to a safe spot.
The layout of the bottom is simple, there is a central area with a giant eyeball (the Hydra) surrounded by tentacles (both minions, and lieutenant versions that split into 2 underling tentacles). The central area is circled around by some broken up boulderish terrain, with 4 equally spaced and partially separated areas containing 1 force field generator apiece between these rocky barriers and the walls. Each force field generator area has a group of 6-7 Rikti (mostly Chief Soldiers with a few Mentalists, Mesmerists, and Headman Gunners thrown in), with a Hatched Kraken (monster class villain) positioned somewhat nearby (although easily outside of aggro range from the generator groups if you are at all careful) at a gap in the rocky barrier, presumably guarding the way from the generator to the Hydra. Everything is level 42.
The first step is to clear the Rikti from the force field areas. This is quite easy and should only take 5-10 minutes. Our strategy was to start doing this at the same time our controller was getting us the Rikti weapons: as each scrapper got a particle cannon he would jump down and start beating up a generator group, and be eventually joined by my defender and the controller once we got our Rikti weapons, at which point a group or 2 would already be dead. This might be a bit tough with less durable (and/or lower level) scrappers than ours, but the invuln scrappers didn't have much trouble defeating groups with 6-7 +2-3 boss/lt's all by themselves (they occassionally died to bad timing and/or poor attention when Unstoppable dropped though ;)).
DO NOT DESTROY THE GENERATORS YET. If you do, more Rikti will spawn in about 1-2 minutes and repair the generator. If you were wise enough to bring a good controller along with several holds, you won't have to mess with these generators at all, saving a large amount of time later when you start working on the Hydra.
Defeating the Krackens
After the Rikti groups are gone, it's time to start putting down some Krackens. The important things to know about the Kracken are 1) it does a nasty AE foot stomp that hits everyone within 10-15 feet of it for ~800 phys damage at level 40, 2) it has a nasty AE spit attack that does ~500-600 untyped or poison/psi damage over 4-5 ticks (invuln doesn't protect from it, for sure ;)) to everyone near the target, 3) it's other attacks are run of the mill big single target physical attacks that only your tankers/scrappers should have to deal with.
Defeating these is pretty easy once you get the hang of it. We used a pretty standard pulling tactic: our scrapper would aggro one from range with TP foe (hiding behind terrain to avoid getting spit on), and run to our pull spot behind a large squarish boulder situated kind of in a "corner" of the wall near one of the generators (perhaps using TP foe reacquire aggro if it was a long pull). This allowed him to avoid getting spit on while the Kracken was closing to melee range.
Then after the Kracken was engaged with the scrappers at melee range, the controller and I would debuff the crap out of him. So, after he was inside a bunch of ugly green clouds (moving at a crawl, attacking maybe once every second or two, doing around half damage, and ~50% more susceptible to damage), me and the controller then just let the scrappers and pets hammer the crap out of him until he was down, staying well out of melee range except for the occassional ninja heal or buff right after a foot stomp. After we got good at this it would only take about 10 minutes to defeat all 4 Kracken, and a fair chunk of that time was spent waiting for Unstoppables to drop or for the Kracken to run up to our pull spot.
At ~88k XP (4 level 38 heroes) to ~55k XP (4 level 41 heroes) each per Kracken, you can level in a hurry here, so make sure you're done with any contacts and/or story/badge missions you wanted to do before spending much time down here (I missed 4 of my arcs, but I can't really complain much since playing around down here and figuring out our strategem was the most fun any of us had playing CoH in ages). We all went from 38 to 41 inside of 20 play hours while honing our technique, despite dying alot and even spending some time in level 39-40 acruing intentional debt so we could get more of the special enhancements to play with (which turned out not to be as cool as we had hoped).
Clearing the Tentacles
Okay, so now everything at the bottom should defeated except for a huge eyeball floating in an ugly green sea of sewage, surrounded by a bunch of upright tentacles waving lazily in the air. The Hydra itself has an assortment of high damage, very long range, psionic attacks. One is a big dot that does 5 tics of 90+ to an unresistant level 40, and the other is a big nuke that does about 900+ damage to an unresistant level 40. So, keeping this guy busy is one of your main priorities ;). The tentacles come in minion and lieutenant varieties; both shoot long range spit attacks for ~100 damage + 5-6 dot ticks of ~10 (I never noted the damage type, but I think our scrappers were resisting it); the lieutenant variety split into 2 underling tentacles when you defeat them.
Now, first things first, have someone occupy the Hydra (in our case this was our controllers Phantom Army and Phantasm decoys), and you will see a shimmery blue force field spring up around him (if it wasn't up already). The Hydra is immune to all damage while the force field is up.
While the Hydra is occupied, commence beating up tentacles. Our approach to this evolved from carefully (and VERY slowly) doing it at range with only myself and the controller blasting while the indestructible pets played with the Hydra, to basically everyone just free for alling tentacles until the Phantom Army was about to expire, then running behind some rocks until the controller could drop in another PA (about 10 seconds down time between PA's), and then wading back into the melee. With a perma army, or any kind of full time aggro drawing tank, the run away and regroup part could obviously be dispensed with, and everyone could quickly clear all the tentacles while the hydra was being kept busy (nearly any paired defender and tanker/scrapper duo should do for Hydra duty, or possibly any regen scrapper all by himself).
Towards the end, we were more or less only clearing a patch of tentacles (about a 1/3 arc around the Hydra) from which to stage our assault on the Hydra, and then blasting the Hydra to death from our clear patch after taking the field down permanently (see below), with me or the controller taking breaks as appropriate to heal and/or EMP/flash the tentacles and Rikti waves out of the action until the Hydra was banished, leaving us free to mop up any remaining villains at our leisure. All told, after getting the Krackens out of the way, we would generally finish the mission 10-20 minutes later.
Defeating the Hydra
Okay, so after the tentacles are out of the way, it's down to just you and the big guy, with that annoying force field in the way. This is where your holds can save you A LOT of time. For us, all it took was this: me and the controller would go stand within range of the Hydra, and do our EMP + EMP + flash, and voila the field was gone and never came back.
I have read elsewhere gravity controllers can knock down the field using singularities, but we didn't have much in the way of strong single target holds to see how effective those were (but presumably enough of them stacked together on the Hydra would eventually achieve the same result). Once you knock the field down this way, you can basically just shoot the Hydra until it's dead, leaving a few members (in our case, me or the controller) free at the key points to deal with the Rikti summonings.
Anyway, after the field is down, you can pull out your particle cannons and begin banishing the Hydra. These things have a HUGE animation time (about 20-25 seconds) during which you can do NOTHING, so be sure the hydra (and tentacles, if you left any) is occupied while you're standing there ghostbustering it's [censored]. I would estimate it takes about 25 particle cannon blasts to finish him off when you are all level 41, probably more like 45-50 shots if you are all level 38.
After The Hydra hits 50% health, he will summon in a large group of Rikti (almost all Headman Gunners, 12-15 or so of them, perhaps 3-4 per person if more are in the team?), so be sure a few folks are not stuck in the particle cannon animation to deal with these (our controller would stop shooting sometime around when the Hydra was about 55-60% health and wait for the Rikti to show up and then AE hold them all with flash + EMP).
At ~25% health, the Hydra will summon another group of Rikti, about the same as the prior one. Again, someone should not be locked into ghostbuster mode who can deal with these (like someone with a big AE hold). After these are dealt with, you can finish off the Hydra, clean up any remaining Rikti and tentacles, and the mission will be completed.
If you are unfortunate enough to not have anyone who can knock the Hydra's force field down permanently, you will have to do it the old fashioned way, which might add anywhere from 10-50 minutes to your trial time, depending on your group's level (affects how much damage you can do to the Hydra in the time the field is down, and hence how many times you will need to knock down the fields) and teamwork (affects how long it takes you to take down the field each time it goes back up).
The field is maintained by the 4 generators you cleared of Rikti earlier, and if you destroy all 4 generators simultaneously, you will get a ~1-2 minute "window" in which the Hydra is unshielded and you can damage it with the particle cannons. After that, Rikti groups will spawn at all the field generators and repair them, bringing the shield back up (at which point you may have done from 1/4 to 1/2 the Hydra's life, depending on the levels of the cannon wielders and assuming they got in about 2-3 shots each) and leaving you to bring them down all over again.
Back before we figured out how to KO the shield for good, our scrappers would "soften" all the field generators by knocking them down to 1/4 or less health without destroying them, to make it easier for us to bring all the generators down simultaneously. If you kill a generator prematurely, Rikti will gate in there and repair it a minute or so later, regardless of whether any of the other generators are down or not. We only experimented with the generators a little before we discovered our far superior strategy, so I'm not sure if there is a better way to deal with generators or not (i.e. if you leave a small team at 1 generator to keep it down permanently, will this keep the field down, or is only 1 generator required to bring the field back up?).
Completing the Mission
Sometime after you banish the Hydra and defeat all it's tentacles, and all the Rikti at the bottom (summoned or otherwise), the mission will complete. I recall at least once the mission completing before all the tentacles were dead, but I think those were only underling tentacles (not entirely sure about that), so I'm not EXACTLY sure when the mission completes after the Hydra has been banished.
Anyway, the special Hydra enhancements are awarded at the time the mission completes. BE SURE YOU HAVE OPEN SLOTS IN YOUR ENHANCEMENT INVENTORY OR YOU WILL NOT GET ONE. I would recommend keeping several open enhancement slots just before killing the Hydra until the mission completes, just in case you get a few from random kills right before the mission ends (I missed getting a few of these from bad inventory management, and/or from getting a few normal enhancements just before the mission completed). For whatever reason, the person whose mission the trial is will not get his enhancement until everyone has left the mission map.
The Rewards
Okay, so what is this Anti Proton Exposure thing you just got? Basically, all the Hydra enhancements seem to be +25% enhancements to several aspects of a power. The Anti Proton Exposure, for example should provide a 25% bonus to defense debuffs, accuracy debuffs, and endurance reduction (read the ingame info on the enhancement to see what it affects). The more useful ones I have seen are +acc/dam (for almost everyone), +heal/-end (useful for many), +acc/mez (mez is a bonus to ALL status effects except slow, highly useful for controllers obviously), +range/dam (for blasters), +accbuff/defbuff/-end (for some defenders), +accdebuff/+defdebuff/-end (for rad/kinetics), +accdebuff/+defdebuff/+acc (for dark/kinetics).
Officially, I have only tested the damage component of one of these enhancements, but it was exactly 25% at even level (all the Hydra enhanemcents are level 40) when I did, and this led me to believe what I have read elsewhere that they provide a 25% bonus to whatever their description says they affect. At level 41, I tested it again, and it provided only a 22.5% damage bonus, so these enhancements also degrade at the standard 10% per level below yours (and presumably increase by the standard 5% per level above yours). Also, I can say with authority that identical Hydra enhancements will not combine, so you can not extend their useful lifetimes via that route.
Hydra enhancements are also reputed to work if your level is within 5 levels of theirs (rather than the standard 3). But basically they provide little to no benefit over a regular +3 SO (which is +38.3%) after they become -2 (only +20% bonuses) unless it was providing at least 3 bonuses you wanted (for example, Anti Proton Exposure is the only one I will be keeping slotted after I hit 42, since it provides 3 useful bonuses in Radiation Infection).
So, they are kinda cool, but very hard to get on your own until level 39 (unless you team with higher level folks), at which point they are only useful for a couple levels unless you have one that is a 3-point (or better) match for one of your powers. Obviously, if you only like one of the bonuses these enhancements provides, you are much better off using a standard +3 SO. These enhancements could make very nice gifts to a level 35 hero who had a well matched power, however.
Possibly, more useful than the Hydra enhancements you get are all the L41-42 SO's you will get from killing all those Rikti bosses, to patch up your ailing L40 SO's until you can replace them with shiny new L45 SO's at SL42. And of course, you can't overlook the ridiculous amounts of XP you rake in from killing all those Krackens (each member of a well constructed 4-man team could easily level every 3-7 hours from SL38-SL41, depending on how quickly you can get all the tactics down pat).