Trying to think of games that haven't been mentioned...
I never got past the first level of Duke Nukem: Land of the Babes, but that was really a flaw in the design rather than the difficulty.
Although Resident Evil 5 wasn't a first person shooter you spend most of it looking down the barrel of a gun. On the hardest setting without carrying over weapons or infinite ammo or anything it was really difficult.
Condemned 2 on the hardest setting got a bit frustrating for me but that's probably because I didn't really nail the combat system.
Time Crisis was really quite difficult with the assigned number of lives.
I never got past the first level of Duke Nukem: Land of the Babes, but that was really a flaw in the design rather than the difficulty.
Although Resident Evil 5 wasn't a first person shooter you spend most of it looking down the barrel of a gun. On the hardest setting without carrying over weapons or infinite ammo or anything it was really difficult.
Condemned 2 on the hardest setting got a bit frustrating for me but that's probably because I didn't really nail the combat system.
Time Crisis was really quite difficult with the assigned number of lives.