343 Guilty Spark
--== Enemy Units ==--
(1) Grunts -- A mixture of both types / a lot are asleep so melee them
(2) Jackals -- A mixture of both types
(3) Elites -- All three types are present / Type-3 are mostly invisible
(4) Squids -- the odd little mind-screwing mobs
(5) Flood -- Mobs of different type taken over by the Squids
Level Notes: You can unlock the following Achievements on this level:
-- This Ones for Jenkins! (10 GS) Kill 50 Flood Combat Forms on the level “343 Guilty Spark” on Heroic difficulty or higher.
-- Breaking Quarantine (25 GS) Escape the Forerunner Facility on the level “343 Guilty Spark” in under 21 minutes
-- 343 Guilty Spark (25 GS) Complete the level “343 Guilty Spark” on any difficulty
You start out in a swamp -- and after you kill the attacking enemy search the base of the trees to locate the Skull for this level -- the Recession Skull -- and then work your way along the path to the facility and enter, battling your way through the various defenders until you reach the room with the burning wreckage -- hop on that to reach the upper level and go through the door there, and you will find an insane trooper who fires on you. Basically you have no choice but to put him out of his misery.
When you reach the next area you trigger a CS in which you view the video recorded on a Sergeant's Helmet Cam... This lengthy CS shows us what happened to this squad -- and the Captain. They are attacked by a new type of mob that appears to latch onto the brain and take control of the body...
It turns out that these Squid are the only thing that the Covenant actually fear -- well, we will teach them to fear us, but still... This must have been what Cortana was freaking out about...
We will do battle with many groups of them before facing Flood, but it soon becomes obvious that we need to get the hell out of this facility as fast as we can!
343 Guilty Spark - The Recession Skull and another two easy to miss Achievements
The Recession Skull
You work your way through the passages to a room with a light bridge you can turn on -- but that leads to a dead-end -- the door you want is in the opposite wall from the one at the end of the bridge -- where you will find a lift to take down into an area where you encounter more Squids and a new type of Flood that uses weapons! Defeat them and then work your way through the next three areas climbing up to reach the chamber with a lift NOW STOP.
You need to activate this lift and IMMEDIATELY jump off onto the platform about 12 feet up with the Terminal on it. If you are playing co-op your partner must ALSO jump, or you will quickly find yourself teleported back onto the lift without the Terminal to your credit and screwed! Seriously, fail to do this here and you have to repeat the entire bloody level! You should unlock the Achievement Breaking Quarantine when you activate the lift as well -- and after you do the Terminal, call the lift and head up where you will meet up with a squad of Marines.
At this point you get your comm back and arrange extraction -- as you progress through the swamp you encounter the Spark during a CS and are teleported out of the area, effectively ending the mission and unlocking the Achievement for this level! Well done!
You should not have much trouble unlocking the Achievement Breaking Quarantine (25 GS), though This Ones for Jenkins! (10 GS) can be a bit of a challenge... If you are doing this level co-op be sure that whichever of you unlocks it STOPS killing Flood as if they don't the one who has yet to unlock it may not have enough targets to get to 50.