mrkgnao: I did like those levels that can be completed almost entirely by sniping the hostiles from afar (that's my primary FPS strategy since I don't know how to run and shoot at the same time --- so apart from sniping I only use two other strategies: stand and shoot, or run and scream).
mrkgnao: I don't think I ever used a flamethrower in any game, hence the saying "a good flamethrower is a sold flamethrower".
My primary FPS strategy is to run away from the games themselves :) Not counting Deus Ex (was a sniper, but used very sparingly, stealth/hack/meleed my way through it as much as possible) and the few minutes of Half Life or Far Cry (uninstalled before any fight), can count those I played, ever, on the fingers of one hand. Exactly. Wolfenstein 3D, Quake 2, Secret Service, some multiplayer Counter Strike and just a bit of Undying. Finished? None, though I got very close in Wolf if I remember right.
Flamethrower though, final fight of Bloodlines. Put a can in that thing when I brought it down once.