What an amazing game. I can tell this is not your first rodeo with game making!
The controls were smooth, and the game is very coherent in all audio-visual aspects - there is a sombre ambience to the game since you start it.
I believe this is a good base to even make a commercial game if you want to expand on it.
I really don't have much to add other than I wish it had more levels and maybe add some optional "challenge" collectibles like the bandages from Super Meat Boy.
Outstanding work, I hope to get to your level one day.