I love this game! The art all fits together. The color blends really well. There's the blue color of the clouds and the brown dirt ground. The ground pixel art looks very pleasing to look at. The floating of the ground though (I mean the bottomest ground) is kinda weird. I would prefer seeing something else there, maybe like vines or something.
This game would benefit with having a coyote time mechanic. I'm not sure if you've implemented that, if you have then maybe you should consider increasing the buffer time? It is kinda frustrating jumping through those obstacles that are one on top of the other. Also I didn't find out about the ramp mechanic until I read the other person's comment.
I really like the vibe of this game, the character's art design and the feel of the setting. My favorite part though is those other stuff you put :P. I think you have the skills necessary to make a great game and story, so please keep it up.