This is a pretty strong entry, but I do share the issues the other commenters have brought up. I think if you varied up the lighting, added some new textures and some signs it would help with navigation. The first weapon sounded like a stapler but it made sense in the context of the game. I found actually hearing the creature on floors above & below very concerning but I feel like muffling the sounds when this is the case would make it a little more obvious compared to times when it's on the same floor as you. I didn't find the lack of ammo to be an issue because I didn't encounter the monster enough either.
Also, I didn't find the AI core immediately as the entry door was covered in darkness, compared to the other doors. When I did enter and get the keycard I didn't notice because I had picked up so much other stuff. I actually restarted the game at this point because I thought I had somehow bugged it out. It was only when I came back in for the second time I went "What's that book thing there?" and realized what it was.
Still, some good stuff here. Good work.