I never fell into a lava pit, so as far I knew, the game had no instant death. I guess that would explain why it seemed unfair to others. The life bar was long and there were life pickups from both candles and enemies, so it didn't seem like I would be in too much danger unless I got really reckless. Instant death can always be a downer. Did you think about having pits only deal damage instead of killing? Hollow Knight and the Shantae games both have it that way. They just respawn you at the beginning of the room and deal damage. I found that really refreshing compared to old school platformers that had instant kills.
As for the glitch, it's certainly possible that it's my video card and not your game. It had some problems at a few other times lately, including when it was idle. It could even be a total coincidence that it crashed at a point in your game where it looked like it was loading something. I thought it might be trying to load the ending or a dialogue. The screen really glitched out before it crashed which it didn't at the other times it crashed, so I thought it might have been triggered by the game, but maybe not. I wouldn't worry about it too much if I was you, unless someone else tells you about a crash. I don't think I'm going to try loading the game again though, just in case it was a problem. My computer is on Windows 10 64-bit by the way.