First congrats to your first game! Honestly a nice idea, but the level design lacks a bit of diversification.
A random jump scare here and there some markers other than the mannequin on the wall, other textures for the floor that would look more like real building floors maybe some random lamps would make huge difference, maybe throw some traps in there as well. Just my opinion I hope you will update the game in the future and make it even more enjoyable!