I really really enjoyed your game.
Art is awesome, music gives a fitting atmosphere which makes gamplay feel awesome to me.
The difficulty curve is good and always puts up a nice challenge to the player by introducing new boxes every few levels. The levels had a fitting difficulty which kept me engaged and playing by giving e a challenge but not being insanely hard and tedious.
I'd really wish there were more levels to this game. I really wanna play it for longer. Especially because i somehow got lucky on levels 7-9 and oneshot each of them. (More proof for how intuitive the game feels and controls)