Fliperama I just got the achievement myself from a pretty good vantage point of the whole room, I didn't notice anything odd other than the sound. I wonder if it's a reference to something?

For Great Souls you need to kill the Crawlers in the areas that are for some kind of boss, like "Chief". Possibly "Administrator", and anything similar. For me, this, Crawler 185 [interactive-game-maps.github.io] was the last one that I was missing, in the "Chief" room on Technical L2 (bring the yellow keycard for the door).

For Garbage Collector, this is what I had in my inventory when I went for the ending, and this is what was left to do. I did not need the blue keycard as I have opened the last door earlier, and also killed the last enemy, so I didn't even need the gun.

Garbage collector, please? there's way more "tools" (as in non-consumable items that solve puzzles) than there are spots in your inventory. Are the hands tools? How about the Flash Drive?

I just got What?? by accident, does anything show on the projector screen? or is it just the noise? I was looking away when it happened

don't understand how to make great souls achievement? only this one is missing

how to get Aimbot,i really don't know how to do.shoot head?or foot?

For the Aimbot one, upgrade the rifle with at least the damage one (disk reader things you pick up, think the red one is damage). With that, you can one shot slashers no matter where you hit them, making it simply a timing and knowledge issue.

Thanks a lot n,n

Bright One can be attached to Double kill by placing mine near cage