right now there's only story mode, but couldn't you speedrun the arcade modes as well?

also, the PC version handles ranking up in story mode differently, you can only rank up once per game, making it take longer before you actually get high enough to move on to the next world, and the GBA version doesn't even have a story mode, just the arcade modes.

Well, the best solution is to just add more specific categories, but really the arcade modes in the Xbox and GCN versions have one rank up per game, so you're just making it a faster version of the PS2 and PC story modes. But more categories for more people to try wouldn't hurt :)

Does PC have a marathon run?

As far as I have been able to tell you can't even record footage for the PC version