Start the game with the "+set cheats 1 +set ui_console 1 +set developer 1" command line parameter. While playing the game, press ~ to display the console window. Note: Press [Right Alt] + ~ to display the console window if ~ alone does not make it appear.
Cheat Codes (demo version)
Start the game with the "+set cheats 1 +set ui_console 1 +set thereisnomonkey 1" command line parameter. While playing the game, press ~ to display the console window, then enter one of the following codes to activate the corresponding cheat function: