Also, there a few very minor suggestions / things I noticed.
1) When the player jumps into an edge or walks into a wall, sometimes the entire screen shakes - this is especially noticeable in the clouds.
2) Key remapping would be nice. I ended up liking the E/F/space placement, but another "classic" mapping could be Z(action), X(throw), UP(jump), DOWN (enter door)
3) Any keys held down while entering a door are cancelled. (Example: holding right to walk and entering a door results in the player standing still on the other side, forcing the player to release the key and repress it to begin walking again. Really doesn't affect gameplay but transitions felt less "smooth"
*spoilers*
3) The throwing hand's instructions for bringing things through doors could be even more dummy proof (AKA dummies like me). Something along the lines of "Throw the item. While the item is still in the air, press to enter the door. Quickly catch the item before completely going through the door"