This game not only succeeds in theory, but also execution. The controls were simple and easy to pick up, and the game actually felt fair, not too infuriating, nor too boring unlike a lot of scripted horror games these days. Furthermore, the environment really helps elevate the horror factor even more. You've hit the spot that few free horror games manage to touch for me.
MINOR SPOILERS: One small critique I have, is that I would suggest next time you make a horror game you give more emphasis to the sound. While it did make me feel lonely, it didn't outright give me the chills, other than the elevator jumpscare. Adding long lasting, high pitched notes or screams, or fast and heavy drums during dangerous situations (such as the elevator siege) elevates stress
Overall, great job :)