Congratulations on you first jam submission!
The pixel art looks gorgeous.
As others mentioned already, the player controller / jump or level design need some adjustments. Either larger platforms or more precision, e.g. being able to control the character mid-air, would largely improve the feel and flow of the game.
Oh and also - i liked the part where the story telling was on the dark background, which towards the second half changed, obviously due to gaps in the map. Maybe the text deserves an extra panel or could be up in the sky.
Nevertheless solid submission, especially for the first one.