perfect dark is also worth playing. there arent too many mission based FPS games with a linear level design/selection.
perfect dark and goldeneye are really the only ones i know about.
also, most FPSs just increase how difficult the enemies are, while these games add more difficult tasks to the game. my only complaint about both of these is i hate the idea of mid-level spawnpoints. completely defeats the purpose of being thorough.
>clear hallways
>clear rooms
>check all corners
>go to open door
>enemies materialize out of nowhere, come from empty room and shoot you in the back.
is it so hard to put an un-openable door so atleast i can be rewarded for paying attention to the environment? "oh, guys may come from this area so i should probably keep an eye open"