The sound effects and music are a joy to be honest. An absolute joy. I didn't really mind getting stuck because I could just stand there and jump and listen to that squish 😂 It sounds like there's another build you'll be uploading after the jam ends, so I'll check it out again then!
The jump feels good, but I think you should make it variable jump height, so I can do little hops. It'll also enhance the gameplay, because it gives the player more options. I think increasing the gravity while you're falling will also help a lot, this gives the player a bit more of a sense of weight. Mario, for example, has 3x the gravity while falling! You can use GMTK's Platformer Toolkit to help you get a good feel for different values and what makes this sort of thing feel good :)