Cute, chill lil' game! The environmental art is pretty nice.
The music was extremely short, I'd recommend lengthening it and adding a B section at minimum to keep it from becoming too repetitive. Some sound effects would also enhance things!
When you get the double jump it isn't clear that you got a powerup or what powerup you got, I'd recommend telling the player what they got and how to use it. I did figure it out though, thankfully.
As a metroidvania, this felt very linear, but maybe if you had managed to get to that other 70% of content that wouldn't be the case? Not a bad game by any means though. Hope you keep at it!