Pretty good game. Consider adding some audio (I couldn't hear anything, so couldn't rate you there)
An indicator for where the players are supposed to go would've been helpful. I spent some time finding the goal of the first level. Telling players that they could climb blocks by jumping to the edges and hitting space again would have been helpful too.
For the first level, maybe give the tiles that you can land on a white border. It was hard to differentiate between them and the background, especially in the lower half where the colors were very similar.