Well, I just experimented around with SSSV and yeesh. Every animal in the stage has their own coordinates, and those determine where the animal is whether you control it or not. Each animal has multiple coordinates, one defined in terms of tile number and one that increments by 16 for every single pixel you move. Not only that, but these coordinates aren't evenly spaced in memory from other animals or even from each other. Now, this wouldn't normally be a problem, as I can easily map games without hacking my position around the level, but almost every single room in the game loops horizontally and redefines the position of the tiles each time you go through a loop because they're not nice even multiples of 256. The first time I tried mapping it the normal way, I wound up too many columns and had no idea where they were. Oh, and I can't even figure out how to activate the souvenir on the very first level. I put the dead sheep behind the ship and barked at least 50 times and nothing happened.
Someone else can have this project if they want it. I'm dropping it and going to Stafy!