Generally a very strong entry!~ Very charming and a lot of fun~
*SPOILERS AHEAD*
I actually didn't know I could use the scroll wheel to change the scale of the puzzle pieces in the final puzzle, so I was very confused, wondering why the pieces couldn't fit. I was stumped until I read the game page. My recommendation is to indicate that the scroll wheel can be used, or simply have double-clicking change the scale (Since that's the first thing I tried).