I've noticed most (if not all) categories don't have difficulty specified, is it assumed that every run is done in tourist difficulty? Why not add a category for normal/serious speedruns as well?

With mutators difficulty essentially doesn't matter, and there's no reason to run this game without them when the classics have much better load times.

You'll find very few (if any) runs are done on tourist/easy cause you can't rocket jump. A lot of the coop runs will be done on serious to get the biggest damage boosts possible.

Oh, I understand. Didn't know about the classics having better load times. Thank you!