Automatic 3Dification of Nintendo Games: The GlEnd() of Zelda
I think the really clever bit is the way he's using save states to automatically figure out the game physics. For instance, he holds the left button and looks for a memory location that's decreasing, figures that must be the X location. Then restores the memory state to before he did that. With that info he differentiates obstacles by trying to walk into them. If it fails, it's a wall (so draw it like a wall instead of a floor). Restore back to the player's timeline and continueHe doesn't say if that's a step he does once per game or every few frames, but given the clock speed differences between the host and guest VM it could well be redone pretty constantly which would allow for games with more than one mode of play