Press ~ during game play to display the console window. Type sv_cheats 1 to enable cheat mode. Then, then activate the following cheats by entering the corresponding codes:
CHEAT FUNCTION - CHEAT CODE Invincibility - god Invisibility - notarget All weapons and ammunition - impulse 101 Fly and walk through walls - noclip Draw your gun; can climb ledges you cannot jump off while it is drawn - r_drawviewmodel 0
