You've made a really fun and innovative puzzle mechanic here, I've had a lot of fun with it. Despite the graphics being serviceable the gameplay is designed very well. I like how you taught the player throughout the levels and slowly introducing new mechanics, and then testing them with some tough puzzles. Speaking of the puzzles, they're well designed and they really require you to think a bit.
My only suggestions would be just quality of life things, like adding sound effects and music, animations, etc. But it's a jam game, and it's fine that those things are missing as long as the concept is there. There also seems to be a bug where the 'about' button also takes you to the level select.
This is great work! I hope this continues to do well in the jam.