Fixed it, it was user error. Admittedly, the OP was extremely vague. The error is that a quad was nil when running love.graphics.draw, but only sometimes. This is due to how my animation module works, which flips through the quads I need to use based on a frame number that increments by love.timer.g...

Game is attached. I've tested on both Chrome and Firefox.

The game runs for about 1-5 seconds before crashing. It looks like everything loads correctly, but then I get a Lua error in the console that doesn't normally break in a desktop version of LÖVE.

Anyone know why this might be happening?