First of all, congratulations on publishing a game! I remember my first game jam too and it's super challenging when you're trying to do everything solo. I really like the minimalistic graphics!
Since your itch page mentioned you were looking for feedback, my suggestions would be to (1) spend a little more time trying to get the player movement to feel good (either via mechanics, game juice, etc.) Try playing some 3d platformers like Mirror's Edge, Titanfall, etc., and pay attention to what makes their movement systems feel good. That would be my #1 piece of advice because the feel of the player controller is priority number 1 in 3d platformers. (2) Secondly, I would suggest adding some kind of tutorial, because it's super disorienting to hit play and immediately die the first few times. (3) Above all else in games like these, you want to figure out how to keep things from getting frustrating. Perhaps you could make the game a little more forgiving by slowing the lava rise speed?
I'm only pointing these tips out since you mentioned you wanted feedback. Game jams are tough, especially when you're working alone. (I went solo my first jam, but the last few years I've worked with others via the GMTK Team Finder tool.) Congrats again on finishing the game!