2.3 HTML5 runtime is very buggy as of yet, e.g. this will cause your game to straight up not start on beta runtime 187:
function scr_a_bug() { var fns = [ function() { return 1; } ]; var ret = fns[0](); }
I try to report everything I find but it's hard to catch all of these when you can't see the next bugs before the current ones are fixed.