Nice discovery, but the movie is kinda weird.
The glitch makes the movie consist of holding Down for some seconds and then Up for some seconds, repeated 9 times.
- You can start holding Down way before it's needed.
- You can release Down way after it's not needed anymore.
- You can release Up way after it's not needed anymore.
- The only gimmick is in a 1-2 frame window when you need to start holding Up while still holding Down.
This is obviously trivial to TAS, like in Duck Hunt where all you need is finding the first frame to shoot and the spot to aim. Then you can be sure that within the existing knowledge base you will always be getting a frame perfect movie. In theory, a new glitch could be found that would make the movie even faster. Overall there are quite a few more possibilities in this game than in Duck Hunt, so in the end it can be considered not as trivial, though borderline. I think it's passable.
As for the starting level, due to the glitch all the unique content and all the difficulty changes have been rendered irrelevant and don't affect gameplay in any way. I made this movie pick option 3, adjusted every level's Up/Down glitch by a single frame
, and the movie completed level 9 without problems. In the ports without this glitch, gameplay differences actually play a role, but not here.
Since this game does loop at level 9 which is still the hardest, it can be considered a valid ending point for a movie. If the game kept incrementing the level count indefinitely, we'd likely accept a movie that only plays through the first loop, because difficulty and new content are irrelevant here (provided they are indeed irrelevant in every future loop too). But this movie's ending point is fine.
What I would prefer tho is starting from level 3. As I already tested it syncs just fine after a few trivial adjustments, so there's no technical problem with that.
DrD2k9, do you have thoughts on that?