Your game looks very polished from the art perspective. The magnet and box behaviour feels also super responsive and nice. For me this alone drove me through all 4 levels. 

In my opinion the game lags some interesting level design. Currently you have to put too much boxes per level in the same way. I think with some clever levels where the player has to make some decisions (level 3 goes in the right direction), this could become a really good game.

My review (Forgive my English, I'm a Spanish speaker and I use a translator).

Aesthetically, it's the most beautiful game I've seen in the jam so far. Congratulations on that. The gameplay is interesting, using only the mouse and one button. That's very good. Perhaps a few details, like making the first level easier and better introducing the concept to the player, could make the game much better.

The main menu and options are very professional, as are the aesthetics. The gameplay is the only complaint.

This is my full review (Don't forget to review my game too).