Hey there - thanks for the report, and sorry for that crash!
I just tried a playthrough on Safari and could not reproduce it :| Have you by any chance tried a second time? If you do end up trying, could you have the developer console open to see if it prints any errors?
That said though, I noticed that on Safari the game has some other unexpected behavior (like, wiping out local storage when the browser is closed, which would delete all the progress). Until I get to the bottom of this, if you're open to a different browser, the game's been tested in Google Chrome and there it has been stable.