I have an AoB for it at last, and, I can tell you, it was a bitch! I tried to emulate the hack in the video, but couldn't, then I went back to basics and looked at the code and we see in the mainscript function:
if (!forward && _root.nmes.pc._x < 60 && _root.nmes.pc._y < 50)
{
clearInterval(intcall);
_root.timetaken = Math.floor(timer / 3.125000E+001);
_root.gotoAndStop("youwin");
} // end if
if (forward && _root.nmes.pc._x > 8110 && _root.nmes.pc._y > 60)
{
forward = 0;
_root.boss.play();
} // end if
The important bits here are the _root.nmes.pc_x bits - this is the player's x position. We see the boss at 8110 and win at < 60. So what happens if we change the 8110 to something more obtainable, like, say 100:
96 05 00 07 ae 1f 00 00 =>
96 05 00 07 c8 00 00 00
Put this in, jump across the gap, kill the first two crabs and amble under the raised platform and suddenly we get the beat the boss medal. Now turn round, jump across the gap and walk off the left edge of the screen and, guess what? We win!
I hope this works for everybody - it was a real pig to do.