Thanks for the feedback! The cave-in section is essentially the end of the game, aside from an incomplete area marked "To be continued".
From what I can gather from the error code you posted, my best assumption is that it may be a hardware or browser error —though I'm not well versed in troubleshooting web-builds, so can't say for sure. In any case, any attempts at reproducing the bug on my device have been inconclusive.