Beautiful art; I'm amazed at the level of polish that went into it! Congrats!!!
Sadly, the situation is a bit worse in the gameplay department, and by that, I mean the player movement not aligning with the level design. Decceleration wants it to be a Mario, momentum-based, good for horizontal movements; however, the level design pulls in the Celeste precision platformer direction. This creates discouraging moments when deaths don't feel deserved.
PS The gravity also felt off, maybe cuz after a flap it's stronger than at the top of the jump?