Feels repetitive to me.
I found this to be a tunnel style game; make it as far as you can.
What makes it different, at least to me, is the multiple maps (which happen to be slightly interactive, in a good way...)
Unfortunately, that's where it really ends. The only upgrades involve the high score, which isn't online as far as I could tell. The maps recycle and after a few "hmmm this area is vaguely familiar" I wanted my bird to die. Music really didn't help at all.
I do have a question though. Why do you have it so when the bird hits something with its feet it dies? That's totally illogical, and it always gets me at first that lack of innovation in this style of game always leads developers to miss simple things like that. It *almost* makes me want to make my own tunnel style game to address just that.
Conclusion; Try harder! Too repetitive!