Hyperdevotion Noire: Goddess Black Heart
You've mastered this game!
This is probably the absolute worst Platinum I've ever gotten in terms of
absolute mind numbing tedium.
To give some insight, Hyperdevotion Noire is an SPRG with 22 characters. You have to max their relationships up by having them perform a move when next to each other. (like Fire Emblem).
But you have to do this 100 times to max one of the relationships out. For all 22 characters, between all of each other.
I can't even remember what my playtime was after doing this.