The questions is to ask about if there will be a category or leaderboard to let’s say any% both sonic gens and shadow gens in one run. Like will there be one of those to allow this? I’m only asking because I might consider doing doing a run like that.

It should be simple enough to calculate both end times together, right? But I can imagine there might be some fear of splicing shenanigans.

There will not be a category on either of the 2 boards, that is Sonic Generations(2024) and Shadow Generations. If enough people pick up a category that would include playing both Sonic & Shadow Generations in one sitting, then it would most likely appear in the Multiple Sonic Games-Board.