Instructions would be nice
I spent the first 5 minutes or so trying to figure out what was going on, since I pressed the left key and the square moved to the left, but it wouldn't move any other direction. I finally figured out that it's "w a s d" to move. You should probably mention that somewhere, even if it's just in the author comments.
Along the same lines as that, if you don't move immediately, then you die, since a square comes out of the left and hits you right at the beginning. This makes it very frustrating when you're still trying to figure out the controls.
I also found the music to be very annoying. An instrumental would have been nice, instead of someone screaming at me the whole time.
The game play is okay - nothing new or exciting really, but once I got the hang of how to do it, it was fairly easy. Being your first flash game, I won't criticize you too much on this though.
Overall, not terrible, but not too amazing either.