Here is what you could improve:
- The jumping, it feels a bit unresponsive
- The camera could be more zoomed out, a lot of times I couldn't see where I was jumping to
- Be more consistent with your pixel art. The pixels of the player are a lot bigger than those of the ground and water. It makes your game look a bit messy.
- The music is basically the same 15 notes looping over and over. I understand if you aren't really good at making music, because I am too, but I'd say just use a free piece of music from the internet or something.
The color pallete is pretty cool though and the movement is overall better than some of the other jam games I have played. I think if you would take my points into considiration it would be a pretty cool retro platformer.