Nice puzzle platformer! The game really reminds me of fireboy and watergirl, and I like it very much. The puzzle mechanics are easy to understand but still fun to play around with. The shadow levels are also very well executed and brings quite a lot of differences than the normal levels too. It's also very cool. Good job on that!
My slight nitpick is that the character's movement is a bit too slow, especially during jumping. I can't count how many times I jumped but just can't make it to the other side and died. I also softlocked myself in level 11, but I guess that's just an oversight.
Anyway, good job!