Recently:
Ninja Gaiden - Alma boss fight: hard as hell!
Took me ages first play through to beat her. second time round she was easy as I saved loads of potions![]()
Emerald or Ruby in FFVII.
Again, was no problems!General Ramm from GOW on insane.
Penance in FF X, massive amount of time needs investing to even get your characters to a stage where they will last more than 10 seconds never mind actually kill it.