In the Body Count directory, type BCCDNSR250 then hit
enter Start a level then press Left Shift Alt B to 
enable cheats: 

Left Shift W = Warps to ant level
Left Shift I = Invincibility Toggle
Left Shift R = Reloads all Weapons
Left Shift D = Max weapons
Left Shift P = Plays current music track
Left Shift S = Stops current music track