BFBC2: Changeable in config files, set it once and forget - Great!
L4D1: Not adjustable
L4D2: Pretty much hacked and is now adjustable, probably be taken away soon
Killing Floor: Must bind a key and press it every time you spawn- Annoying
MW1: Config files - Good
MW2: Locked FOV65 are you [censored]tin me! Why I will never buy this game
ES IV: Must open console and type in again after talking, sleeping etc - Annoying
Doom3: Haven't found a way yet
Call of Cthulhu: Config tool yay! - Why I keep playing this interesting game
Borderlands: Config tool I'm pretty sure
Some examples there, TF2 is the only game I have heard that a has a FOV slider in it. What's the deal game devs? Stop thinking its exploiting/cheating because that's ridiculous! Tell me I can have at least 100 FOV in Brink and I will go pre order now!
