The game is interesting in concept, I like the idea of each birds having different abilities. The rocks has a weird mechanic where you basically can just stand on the rock and fly away... Also I'm not sure if you've noticed but I think the movement is jittery. I suggest using Fixed delta time for that.
The art style is good, I like the silhouette, but I think the falcon in the first boss looks a bit too similar. Talking about the falcon... My frames were dying every time it dashes down 😭. I got some really funny moments where I just got launched into oblivion and the falcon would not know how to follow. The boss fight itself is also a bit hard.
That's my experience with the game, have a lovely day!