Wow, thank you so much for your in depth feedback, warms my heart :D
All sounds are indeed done with my mouth, which was very swift to do and i was able to set the "idea" of each sound like i wanted. I spent some time looking for music, but didn't find anything that really fits and wouldn't be annoying - very difficult for a kind of abstract game like this i think. I agree with you though ;)
The sprites are done by my wife actually, with whom i made all the games on itch for game jams. She was so happy to read what you wrote! :D
I wish i'd have had one more day to tune the levels and mechanics. I only spent about an hour on the levels with no playtesting by someone else, so i'm really happy they turned out decent enough anyway :D
On the tutorial, i agree i have a todo there. I am a big fan of learning the mechanics myself, with nothing being explained - but this is not for everyone, many people like to know the rules before playing. So i'm experimenting how to fit both worlds. I'm probably just gonna ask the player first what style he likes, so to speak.