Nice game idea. It could possibly do with something to encourage progress, like a time alive or score. Also, a life counter. But the gameplay mechanic is simple and great.
Thanks a lot for the feedback! I was thinking of at least speeding up the game as you progressed, but I encountered too many bugs and didn't have time to fully implement the feature, so I disabled it. I'll try to implement that feature as well as some others, while still trying to keep it simple and minimalistic.