The puzzles are well-designed, and the pixel art is very clean and cohesive. The difficulty curve is also very good.
In level 5, if you push the box directly into the pit, it won't trigger the button, even though it seems to stay on it. I eventually figured out the intended solution. However, a visual aid showing why this wouldn't work would be helpful - perhaps the pit could be made wider, so it's clear that pushing the box down directly won't allow it to stay on the button.
Still, it's one of the most polished games I've played so far in this game jam.