During the game, make your character stand and hover the pointer over the kneeling icon. Now hit F11 to bring down the console and you can enter the following cheats:

Code Result
BINGO Give your characters 999 ammo
GOODLUCK Add clover leaves
IMMUNITY Enable god mode
CASH Get free money
MERRYMAN Get a merry man
UNBLIP View all characters on map
TIMELESS Stop the clock
WINNER Win the current mission
PAM Enable dum enemies for close combat