Wow, this is an excellent little puzzle game! I'm sorry it hasn't gotten much attention - if I had to guess, it's probably because the thumbnail images are deceptively plain looking, so you might need to throw together a more focused/styled cover image in the future for the itch page.
Out of curiosity, is the game supposed to continue after the second set of levels? After I clicked 'continue', the game visually bugged out a bit with some duplicate assets and I was brought back to 2-1 again. I was hoping there would be a bit more, because the puzzles were very intriguing and the expansion mechanics between the two characters just worked so well.