It looks pretty good. I like the fact that it's simple, and easy to understand. I like the launch screen quite a lot.
Here are some things i think you should add.
Instructions: It took me a while to figure out the controls.
Better graphics: Now I'm not saying anything 'next gen' but really it looks like you spent five minutes in paint on them.
More room to move: Ok, I know you spent 7 hours on it, but I honestly think you need more room to move, and not just up and down, but that will take a while, I know.
The wall should change so that we know how much damage it is taking: The subheading, says it all. I think you do need to see how much longer the wall has before you die
When the wall breaks don't die instantly: Give us a chance. On the first level you have about 5 seconds before the wall breaks, and you die instantly.
Apart from that; It's
Great!