Includes 2500 ARC Coins, Premium Cosmetics, Digital Art Book, and Digital Soundtracks.

Arcadegeddon Art Book
Once the art book is downloaded to your Steam Library, you can find the files for it in your Local Files. Right-click the name of the game from the list of games in your library, click Properties, go to the Installed Files tab, then click Browse. You'll find the art book in this folder.