Dishonored 2 will make you earn its Platinum Trophy, it sounds like- according to the listing of Dishonored 2 trophies that appeared on PSN Profiles, the game’s Platinum Trophy, which you only earn after first earning the other 50 Trophies, you will need to complete the game and without killing anyone, finish playing as both, Corvo and Emily each, and finally, in low and high chaos and without supernatural powers.
Given that most of those things can be combined into one play through, you are still left with having to finish as both, Emily and Corvo- meaning you will have to play through the game at least twice (and make life very difficult for yourself, with the amount of stealth the game is mandating), to be able to earn the Platinum Trophy.
For a single player only stealth adventure game, I do think that’s as meaningful a way as any to add replay value. Dishonored 2 launches on Xbox One, PS4, and PC later this month.