I love the concept of the game. Got stuck on some levels too cuz of the complexity!
Pretty fun game to play, although I think music would've made it better too. But I wouldn't blame you if you couldn't or didn't have the time to make music.
The sound effects were great. Nothing much to say about that.
Took me a few levels to understand how things work like nns said in his comment.
Overall I give it an 8/10
Good job!