Visually and audio-wise, this is very impressive and I hope you continue to polish this game! You nailed the theme of the game right on as well.
Nits:
- It took me forever to figure out how and when to use the Z key. Clearer instructions on your game page would help.
- Sometimes with a screen scroll, I would get another bird added to my roster of birds, plus other items like feathers would double, triple up, etc. This would cause a lot of clutter and a fail when hitting something bad.
- Dang, those are some POWERFUL feathers when doubled, tripled up, etc. They would send me through more than one screen and right into a wall :O
I have caught comments on the R key. It did do something for me. The shake at the start of the game was mildly entertaining.
I think a bit of cleanup on code is called for. Otherwise, this is a very solid start and is worth developing more when the jam is over.