Had a little spare time today so I played it for a bit.
Your music has a terrible dissonance in the beginning. The way you continue to develop it in the level sounds better, but unfortunately the moment it starts getting good you loop it. My tip make the music more harmonic and longer before it loops.
Gameplay is super hard. I would like some checkpoints, but I managed to get to level 3 (not sure if it is actually level 3) there I encountered a bug that didn't let me jump over the stack of red exclamation mark containers (idk what to call them), so that was that. You should look into that.
Also you severely underestimated my will to glide over the see of lava just to see what is on the other side. It wasen't long enough. You shouldn't bother making it longer, just attach a script to the player that resets him after you are below a certain value.
Not too bad for a beginner.