A hack of Super Mario Bros. 3, which can be found
here.
All the discussion at the 'Super Demo World: The Legend Continues' got me thinking of other hacks which might be good enough to do a TAS for. This one immediately came to mind. It's one of those hacks which changes nearly everything, leaving virtually nothing of the original game behind.
Well, perhaps it's not THAT altered, but it is nearly a completely different game using Mario 3's engine. And even the game's engine was modified quite a bit. I could explain it all, but the page does that. There are new power-ups, new items, new enemies, even random weather-effects for the levels.
Basically: You have access to the first 7 worlds right away. In one level in each of the worlds is a hidden key. In order to unlock world 8, you have to find they key in each world, and beat the Koopa kid as well. There's no warping past worlds, you have to do all 7. But you needn't finish all the levels in each world. When you beat a Koopa Kid, you get a hint as to where the key is located for that specific world. Luckily you can reenter any world and any level. But for a TAS that wouldn't be necessary. World 8 is divided up into a level based on each world, at the end of which you have to fight Bowser, and he gets harder and harder each time.
Myself, I played the hack when it first came out, found all the keys, and got to World 8, but I could never get past 8-7.
This is certainly a hack worth thinking about, though it's up to the admin as to whether or not it would be an officially accepted one, like TLC.