This is amazing!
I've seem a lot of games in this jam where you can change the size of things to progress but this one is the first to do this is a creative way. When I used the hat to shrink the block and the had grew, I thought "huh, that's smart" but then the game keep going and each level introduced a new element to the puzzle mechanics in a very clever way.
There was a point were I was "Ok, so I storing hats is a good thing" and them came a puzzle were I could not progress because my hat was way too big. That's completely blew my mind, because you managed to include new mechanics without actually including new elements.
Also the visuals and sound effects were great, really fit the theme of the game.
I had a problem figuring out the reset map puzzle room, because I did not thought that pressing 'R' was part of solution.
I can totally see this game being released on steam as a full game.