This is very well done mechanically I think, as any qualms as I have about the mechanics can be attributed to it being a nightmare[The slow running and having a hard time with jumps being a common trope in nightmares for example] although the way platforms will push you up if you don't quite make the jump but your legs still touch the platform is kinda off putting to me.
My main problem is that it felt as if you were expecting common nightmare tropes to carry the atmosphere of the game in a short platformer. The problem with that is you begin immediately subjecting the player to "disturbing" imagery, which out of context is just something that the player can easily walk by without having a second thought. Point being it lacked incentive to feel anything because there was no baseline of "okay". Just immediate doom and gloom.
That said that problem was cured near the end when running away from the eye, that was where your game shined. I had incentive, "Run from the eyeball representing paranoia". Also very good use of audio.
I'd suggest adding a little bit more context in game past, "It's a nightmare".