My thoughts after playing the game for longer:
I like the intro in the beginning that also serves as an explanation for why the bird doesn't simply fly over all the obstacles.
I like the graphics and audio. I especially like the particle effect on the death animation.
I like the mechanic of jumping off the enemies, the respawn time on them is perfect.
At some stages (after leaving the cave) the difficulty got a bit steep for me :D, I was hoping for a checkpoint after a long and difficult section but there wasn't one. Maybe an extra checkpoint here and there would be a good idea? I will retry with a controller next time and maybe I'll do better.