Cool game!
I found it very hard and I couldn't move out of the way fast enough on the first levels because the blocks were so close.
Also, nobody wants to sit and read alot of text before playing a game to be able to understand what's going on. Creating a small tutorial or even having the text in game can go a long way. (especially in a game jam)
I also think you should introduce new block one at a time, maybe just have one type of block on the first level so the player can get familiar with all of the blocks.
But it definitely has potential!