I made an error, I meant to say, Hasn't, not has. I'm posting too many comments!
I have seen games with puzzle pieces, but not as characters yet.
Even so, your game is extremely polished and fun to play! The inverted gravity mechanic is a real brain bender, and generally, the game is snappy (Pun definitely intended), and a blast to figure out! You really have a fun game on your hands!