Batman Arkham City

If you do not have a Steam account, you will need to download the client from the official website, install it and then create your account. Once you are logged into your account, click on "Add game" in the bottom left corner and then on "Activate product on Steam". After a few clicks on "Next", you can finally enter your CD key, the game will automatically be added to your library and the download will begin.

More information on Steam

To activate your game with Epic Games, log in to your account on their website, click on "Redeem Code" at the top right of the page, and then enter the game's CD key or code in the field provided. Click "Redeem" to verify the code and add the game to your Epic Games game library. You should now be able to download and play the game from your library.

Learn more about Epic Games

Once you have bought your game, you need to use your Game Code on the Playstation Network to download your game. To access the Playstation Network, you need a Playstation 3, a broadband connexion, a PSN account, and a storage device according to your console: Hard disk drive, memory card, or USB drive.

Use your gamecard Microsoft Points in the Xbox Live Marketplace of your Xbox 360 to purchase full games, rent the latest movies in High Definition, add downloadable content to your games. Exploit the full potential of Xbox Live!
To access the Xbox Live Marketplace, you need the following components and services: Xbox 360 Console, broadband internet connection, Xbox Live Silver membership (included in the product contents of the Xbox 360 entertainment system), Microsoft Passport account, Hard Disk or Memory Unit for the Xbox 360 Console.

To activate a game you download on GOG Galaxy, open the application on your computer, log in to your account, click on the menu icon, and then select "Game Codes". Enter the game code in the appropriate field and click "Continue". Once the code is verified, the game will automatically be added to your GOG Galaxy library where you can download and play it.

Learn more about GOG Galaxy.