I really liked the little feather cursor that you made, the menu looked super snappy and interesting. I was sad that it kind of disappeared once the game started, maybe I did something wrong but I never the cursor again.
I agree with what some other people have said that this game feels a little frustrating, and I think I know why that was for me - it's like you've made a puzzle game, but as a player I don't know what the end goal is, and there's no indication that I'm making any progress towards it. Usually in a puzzle game the goal is pretty clear, but the way to get there is hidden and you have to discover it by trying different things. In this game you've hidden the "how" by not giving the player any help with controlling the bird, but you've also hidden the end goal ("what am I supposed to be doing?") and hidden all the player's progress ("are these things I'm trying making any difference?") I think that's what felt frustrating for me, feeling like I didn't have a goal and I wasn't making progress, until suddenly I finished the game and I still don't really know how, or what changed, or if I did anything differently.
Aside from that, I really liked the game, I thought the graphics were cute, the little bird was fun to swoop around and the sound effects were really nice. I liked the general vibe, and it felt like there were a lot of art assets for such a short time!