Very simple mechanics, but done really well! I feel like there should be more user feedback with switching characters and interacting with levers, like a sound effect or a little particle "poof" above the player when they activate something. I love that you have to move the box carefully to get it to stay on a button as it is slippery, that is unique.
Nice work on the music as well! A Quirky melody which fits the 'quadratic' (math-themed) feel of the game.