Press the console key ` or tilde ~ (between the Tab and ESC keys) and type “e_cheats 1” to enable the developer cheats. Note this will show “Cheats enabled” in the top right of you screen. Turning off cheats again via “e_cheats 0” marks your current game as “Cheated” in the top right of the game.
Cheat Code - Effect:
god 1 - God Mode
infiniteammo 1 - Infinite Ammo
infinitedash 1 - Infinite Dash
give_experience NN - Gives Experience
listenemies - You will get a list of all enemies (actors) in a level