press Esc to access the menu
press F1 to access Help
press F2 to Save your game
press F3 to Load your game
press F4 to access game options
press F5 to access Display options
press F6 to Save your game
press F7 to quit Your game and Return to the Main Menu
press F8 to toggle on/off ingame messges, but you will need them
press F9 to load your game
press F10 to completely quit the game
press F11 to make the screen's gamma brighter
*note the "gamma" scale is 1-3
it will reset after 3 
so either dont press F11 if you dont want brighter Gamma
or if you do it and change your mind, press F11
untill the screen goes back to NORMAL

press F12 to spy on other players
but this is only for ONLINE PLAY/DEATHMATCHES