Honest critique:
Upgrade the dialogue so that the main character doesn't sound like an angsty teen who just learned how to use cuss words. Flesh out the story using intelligent and expositional dialogue.
Spread the enemies out so that they are in more varied locations. There are so many hallways, rooms, and spaces completely empty where enemies could be. Instead, you get areas where you are bombarded by hoards.
There are a couple of areas I found that depending on where you move, some enemies do not trigger/spawn. The spiders for instance, did not spawn during my first playthrough, but did in my second, when I walked over to a certain wall. Another area where the bigger "gas mask" enemy spawns, he kind of glitches and just stands there, or doesn't spawn at all.
Make it more of a struggle to find keycards and add puzzles in order to make progressing more challenging.
The game has a really, really good foundation, it just needs some meat (substance).