Wanted to speedrun a game with my sister but Im bad at the first part and shes bad at the last part. So Just wondering if a run could be submitted and counted if more than one player runs the same file.

I think it'd technically be a co-op run at that point but a decision on it being legit is ultimately down to the game's community.

I'd suggest practicing the first part and getting your sister to practice the last part, it'd be a lot easier. 😛