Oh wait... that's not right...
Hah, I fixed that and then proceeded to upload the wrong file. Durrr...
You're obviously right, I was under the impression you were talking about having no subfolders.
Fixed! (Link updated)
About the balance, yeah, hard to make out without testing.
Right now I think it might be easy for humans to camp their main entrance. (in ubp at least). So I might open up some walls to create some a loop rather than the linear hallway that does into the base now. Aliens might need some more cover in their base and outside, but I'm afraid I might have a bias and make it pro alien in the process. Needs testing.
The lift shaft is a bit problematic. You can block the elevator to the upper position by siting on it. I'll probably switch it for a triggered func-train and give it a roof (so dretches can't crush bsuits by landing on their heads). I might also try having 2 elevators to work in tandem, to avoid the elevator becoming a bottleneck. Ladder could have some end caps to make them easy to get onto. I've added a cushion brush at the bottom of the shaft, so you can jump all the way down without taking damage, that's not very realistic, maybe I just need to put on a texture to sell it.
Visual wise still pretty bland, though I like the overbright sunlight on the upper parts, probably keeping that. I'm also gonna have a granger statue, haha.