Very neat idea mixing 2D and 3D projections of the world for this!
Really liked the squash and stretch on the player character, movement and animation for them felt pretty fluid. I kind of liked that I could move the character in the two-dimensional plane by pushing them with the projected box, made the two worlds not feel too disjointed.
I think I would have preferred if the 3D view simply panned back and looked at the game world head-on or from an elevated angle. While the side-angled view is pretty cool, it did lead to a number of scenarios where the controls for the box went off-screen, and it could not be interacted with without moving the player character.
Definitely a neat idea, would love to see what else you could do with the base concept!