Way to short. Does not feel like a complete game at all. It was way to easy. Music is extremely annoying. You should make it possible to use arrows instead of just a and d.

Wow, that was pretty good! I enjoyed playing it. Here's my review,

Okay here are the things that I think needs improvement on, For the first thing I would say the environment and game asset designs. You got the basics down, now all you have to do is add some different texture, or something other than, a gray, plain, box. I think the wall/goal changing to green animation needs a little better transition.
I'm sure you are aware of the UI not appearing glitch so I won't really talk about that. But there was one time where I was stopped in between 2 blocker which i was clearly not touching either of them, I was confused at what happened. And I'm going to admit I ruined the ending for my self, I exploited your wall barrier to prevent to the player from going off of the map. I found out that if I hold the arrow key in the direction towards that wall I can slow myself down and stop myself. And basically restart my speed. This is how I cheated my way to the end, to which didn't feel very good. The very next time I went in to the "zone" and reached the goal! Which was very surprising and I felt accomplished.

Here are the things I liked-
The music was great, it went with the well with the game and your UI was simple and user friendly. The level design was pretty good I have to say. I tried many different paths and there were many different ways I could have gone. I liked the way how you funneled the player through this... forest of "cement" blocks. The difficultly of the level was perfect. (For me at least) It wasn't easy, and with all of the different paths you can keep the player trying over and over again until he or she gets it(or gives up in frustration) Either way good game and I hope you keep improving this, and keep creating other stuff in the future. Have a good one.

I made it to the end on my 2nd try... :/