I liked the puzzle design on this. I wish the restart button just restarted the level instead of the whole game. I got to a point in one level where I couldn't get out, and restarted all the way back a few levels which wasn't fun. I think some music would really help the game feel. And some way to have dragging the block onto the platforms not move both simultaneously would have felt nicer too.
But overall I think this is very well done :)