A few little problems. Down-drilling into the side of a stalactites repeatedly hurts you which seems odd. It can be easy to fall right into the lava before even seeing it's there if you're unlucky and I must've softlocked the game after falling into the lava by pressing space or some other controls as the menu was popping up, I was left with just a screen of the lava filling it up.
Great jam game. I noticed someone else didn't like the lava in the comments. It's a good way to break what would otherwise be an infinite loop, my only problem with it is it's a "did you keep your Jet fuel? if not, die" check that could've used some jet resources near the lava level.
Reminds me of Miner Disturbance (Funorb, discontinued). The rising lava in that game and the nature by which the lava was triggered made it terrifying.