Since Call of Duty uses the same base for most of its game engines, many commands remain the same throughout the series. The console can be used for testing and to give information useful to the developers of the game, generally for debugging, hence the term 'developer console'. The console can be used to significantly alter the game, including but not limited to making the player invincible, obtaining a weapon that would normally be impossible to get, free-flying, changing game rules and more. Developer console is a tool available on video games, which is usually accessed by pressing the tilde (~) or grave key (`) key (the key may be different for keyboards with different language set-up it is usually the key to the left of 1).