I've only finished Arke so far, and yea it's a huge grueling slog with the constant mandatory backtracking and respawning killbots... on the other hand, it felt kinda fun to be put under such pressure for once, it gave me System Shock 1 vibes. I didn't use stealth, but was still able to do all the lockpicking/hacking needed without getting locked into combat. The robot spawning is on a timer and they're on a fixed patrol route (as long as you don't get spotted by a camera or piss the AI off by trying to disable security).
Basically:
- Start from the main entrance ("central area"), head to eastern area to get janitor keycard
- Get back to the central area, enter janitor room in SW corner, this should get you some more keycards
- Go back to eastern area, use your new keycard to enter door in NE corner (...yeah), get past all the production line stuff and take the ladder down
- Fun times with crawlers, more fun times with spiders (seriously, fuck that room). Eventually you find some more keycards, another hydraulic part (I think) and get to another ladder.
- Take the ladder up and enter a big assembly line area (I'll just call it "western area"). Kill the industrial robot and dodge the rest, kill them as they aggro. The terminal here opens the backdoor to the facility (to this room) as well as opening a shortcut to the central area and powering the elevator in the northwest. More importantly, take the stairs up and get the keycard before taking the shortcut to the central area.
- Go to the northwestern part of the central area to unlock the exec's room with the keycard, get the power control thing (finally!)
- Go back to the western area, take the elevator, deallocate power from security and robot production. This will stop the robot respawns, though you still have to kill the ones that are currently active.
- At this point you can reallocate power to other parts of the Deep Caverns (needed to enter some areas). Annoyingly it's not possible to kill the AI by depowering the IRIS area, and even though it's possible to enter it now (you can try the "open IRIS main access" option at the entrance and it'll work, allowing you in there), it's just a big room with unopenable doors and constantly respawning robots. Will have to come back later, probably.
Power switches in Arke seem mostly useless. I used the power switch in the eastern area and the one in the central / western areas to disable the shield rechargers for the robots, but it just turned back on by itself (wtf). There's also a power switch in the basement next to some plates that alternate between "electrified" and "safe", but it doesn't seem to do anything either.
I found two hydraulic plumps so far (HS-78, HS-83), and at least one of them was from Arke. The other one was either also in Arke or in the southernmost Tchort area (the one directly adjacent to the deep caverns 'entrance' with a lot of breakable walls). Be sure to search the big assembly room as well as the underground section.
BTW, I really really hope there's a way to punch that HK-47 / SHODAN wannabe in the
faceCPU for all the aggravation it caused me.