This is a great game!
It's a complete platformer with great level design and cheeky twist on controls that make this game unique. Even something that might be initially frustrating is soon reasonably solvable, because of the great design of utilising the game's current state, e.g. the subtle change of angle of the box, when near the edge, a "buggy" wall jump that actually is intended and level design completes it.
Great game for a game jam - huge congratulations on making it!