First one that came to mind is party leader death -> Game Over in FF XIII. If you design the game around it I'm sure you can make it work (though ), but FF XIII is not one such game. The game is fast paced, danger comes in very quickly, there's no Defend command or anything of the sort for emergencies or being targeted by a big attack (short of switching to Sentinel, which you won't have for huge swaths of the game), there's no real way to prioritize the party leader's HP being kept in safe thresholds. It feels like something you have to awkwardly play *around* rather than being a natural part of the combat system. Like, you can play around it, sure, but it never feels good.