Some coyote time on the jump would be nice but the thing is, that idea may or may not work for this specific game.
The visuals and arrangement of the levels are really good and the effects like wind add a lot of depth to the game.
When it tells you how to double jump, the text is too high out of view of the camera and the instruction cannot be seen without already knowing how to do it, sort of defeating the point of it. Guess it was just intuitive enough anyway even without the instruction.
Other than that I think you did a great job on this game and it's fun to play!