Really nice style and cool concept!
Goods:
I really enjoyed the idea, Having the player have to logic their way around where to put the boxes. Really cool gameplay loop that could definitely be elaborated on to make some wacky levels! I got to day 4-5 personally. The graphics are really simple and I feel like they add to the feeling of the game
Improves:
The game doesn't perform that well on my PC, So perhaps needs some optimisations to feel much smoother. Asides from that, I didn't really have too many problems with the actual gameplay section of game. Could definitely improve on the sound front if you perhaps added music?
Overall I'd give the game 6/10, Although that's mostly because of the performance issues.