Very nice puzzle game! The song definitely fits the whole mood very well. Though, during the main room where you can select any level, I was jumping around near the levers and stuff (because I usually like to get a feel for the movement haha) and after a few seconds, the game seemed to freeze? Actually, I was jumping around again in the level selection room and then it happened again. Though, it only happened when I was jumping near the levers in the level selection room, seemed kind of spontaneous so I have no idea what could have caused it. I had to close and restart the game to fix it
Other than that, I liked it a lot! Adding some more levels and mechanics would definitely yield a very nice puzzle/platformer game. Overall, a great job!