I think this should be a category. In this category you have to start on a new file, beat Basketball, Hockey, Dodge Ball, Volley Ball, and Sports Mix in one run, so basically beat the game any% kind of if you want to call it that. You will Know if you've successfully completed this run if the background is pink on the sports selection screen. Time Start when you Select the file for the first time and timing ends when you blow the late hit on the Behemoth on Sports Mix. This category can be also play in Co-Op mode as well

I'll add the category once someone does a run of it

Rules: Timing starts when opening a newly created save file the first time (creating the savefile needs to be shown in the video). Timing ends on the last hit on Behemoth in the Sports Mix Star Cup. All cups in all sports must be completed in order to unlock the final Behemoth fight in Sports Mix.

So you have to fight Behemoth to unlock Sports Mix and then fight him again after Sports mix? Also, there will be a co op category for this right?

Yes, you have to fight Behemoth twice and yes, there will be a Co-Op category

Actually in sports mix you have to beat the Behemoth king, so I guess this is the final goal of the run

Next time I go to my friends house, probably within a couple of weeks, we’re gonna do this speedrun co-op. I may do it solo before then too but I doubt it. So you can expect it by then. We’re pretty new to it though and I can imagine it will be FAR from optimized, and easily beatable for any of you people who have been playing this for a significant amount of time

I'm also willing to run it soon, but solo in my case