It's very easy to miss the text cutscenes that appear when you fly, one flap-wing input and it just skips one. I'd recommend have a minimum waiting time for when the screen changes, or have to click on a button to make the text moves to the next.
The controls are really really too hard lol. I think if you just made the movement of the Dragon be linear on the screen from arrow keys it would just be more fun to play coz right now it's just frustrating? idk, the momentum really goes crazy and it's so hard to just fly upward sometimes? idk idk
Also it's also not clear why you needed depth, because the planes just stay static ? Why not just put them all at the same depth and as long as your mouse is dead on them it's a sure shot lol? If they were flying and their depth were constantly changing I could see the point of depth (though it would make it also a lot harder lol). Well maybe it happens later but I cant get past the second wave lol.
short lived playthrough: https://www.twitch.tv/videos/1827577710 (sorry if my english is bad / i sound rude sometimes my bad)
I'll keep trying for a bit until i beat this second wave lol
edit: gg i beat the game https://www.twitch.tv/videos/1827588837