Cool little platformer! Maybe sound could use some improvement. Level design wise there were some blind jumps where as I couldn't look down, and the red box wasn't really explained very well until I got hit like 3 times by it and figured it out. The vertical section had a lot of bonking which didn't feel great either. Visually I recommend picking a color pallet prior to making assets, as it helps make everything mesh together and you can make it super easy to make enemies and the player in contrast to the background. Overall though that was a pretty fun project. Good job!