[quote]It is a legitimate category rather than a challenge, as it is recognized in-game[/quote] You say that like it's required for a category to exist, a plethora of games have categories based solely on the self-restraint of the player. Ocarina of Time doesn't recognize if you used glitches or not, Super Mario World doesn't have a special ending for your exit count, they just care if you get to the end of the game. If the game recognizing your accomplishment is mandatory for a category to exist, we might as well wipe most of the games off this site.
We moderators have revisited the categories that have been requested to be added and have decided to officially add co-op categories. Running these categories will be great fun. Please feel free to give it a try!