I really really liked this game! I think you did an excellent job on the level design. Although just simple blocks, you fine-tuned the levels very well. The controls felt nice and tight. I'd love to see you take this idea to the next level and attach a theme and story line to it. This game has good potential for speed runs, which may be a good idea to add. Maybe a clock and a high score to see how fast you can pass each level.
Great job!!
I also developed a platformer game. I'd love to get your thoughts! :)