Overall, a 6.5/10 for me
The theme was not met, as there's nothing summer-related to this entry.
However, I'll have to say the limitation was met perfectly.
The audio and art are pretty polished.
One nitpick, I feel like the UI needs some work as I did not notice the top left text telling me what not to do (and therefore I was kinda frustrated).
Also, there was one noticeable and common bug, which you can trigger by putting a box inside another object (press S while directly facing an objects/obstacle), and losing that box.