This is truly a high-quality puzzle game! The mechanics are very good and well thought out. It took me quite a while to do the final level, and I am looking for more, but that's probably too much to ask for in a jam. It's quite challenging too! The cute pixel art style helps set the vibe, and the music is very nice and charming! I like this very much!
The few criticisms I had for this game is that I would really want a quick retry button and possibly an undo button. I know the latter is quite a lot to ask for, but with a difficult puzzle game like this, making the players start from scratch every time they make a mistake is very punishing. I would also suggest making the stacked colours more noticeable as it's currently very hard to view which two colours are stacked together at a glance (I hope that's not intended though).
Other than that, this game is a very solid and well-designed puzzle game! I like it a lot. Well done!