Press [`] to bring down the console, then type any of the following cheat codes:

Code - Result:

bot_kill - Kill All Bots
cl_levellocks 16382 - Deleted Scenes
restart - Restart Map - Don't Lose Goals
sv_cheats 1 - Toggle cheats.
god - Invincibility.
noclip - Go through walls.
notarget - Enemies do not see you.
bot_zombie 1 - Make them just stand there.
bot_pistols_only - The bots will only buy pistols.
kick - Kick the bots.
bot_sniper_only - Bots only buy snipers.
bot_goto_mark #number - Make the bot go to specific places.
bot_difficulty - Set the bot?s difficulty level.
bot_knives_only 1 - Bots only use knives.