Great idea for a puzzle platformer and I think the first three levels had a good difficulty curve (I didn't make it past this). My 2 cents:
The controls being told to you the way they were was a little confusing (i thought it was a typing of the dead situation).
Maybe you should turn on friction for the physics objects? The second puzzle was a little frustrating cause the boxes would start to slide away and keep going till they hit the edge.