Wow, this is a REALLY GOOD game. The puzzle mechanics are taught well to the player, and the stars are lovely. The difficulty felt very well adjusted. The level design is immaculate. I couldn't possibly comment on how to make it better, or even make a fraction of it myself.
I'm retrying levels, enjoying mechanics, trying to up my best move count. So far, I've only cracked the first 12 levels, but it's been really enjoyable, and I'm trying to maintain a 3-star streak. And to think there are a hundred or so?
You mentioned this is your first game jam entry ever. Well, this is incredible work. You have a great start, and I think you should keep the momentum up. All the best!