Seems like someone else is looking to run this - cool!
Outside of Any% I would like suggest that we consider at least All Bosses (Self-explanatory), and possibly 100% if a sensible definition can be reached (presumably this should be all weapons, cats, quests, upgrades - but verifying they've been done isn't so simple, cats especially).
It already seems to me like Any% is going to be less than 40 minutes, and its not a long game in general so I can see people going for the extended categories (I want to do at least one shot at all bosses once I record an any% run)
Any%, All Bosses %, 100% (meaning all health upgrades, all weapons, all beast upgrades, and all kitty cat locations), and Revolver Only%.
I was also thinking of something like a "reverse order%" meaning you start from the Yorke Ruins bosses and make your way back to the forest bosses. This is plausible since the world is pretty open just from the start.