I had a lot fun playing this. Everything from the level design to the art style (though, as I said in another game with similar pixel art, I do like to have more colors, but that's just my personal taste) is great. It has those VVVVV vibes and made me wish for a bigger games with bosses and all.
So I do get the "turning up the heat" from the fact that we're in lava cave. Does the "multi-use" stems from the shoe that's also a weapon ?
Anyway, I had an awesome time, thank you !