Castle Crashers is a cooperative 2D beat-em-up game with role-playing elements. Players take the role of a knight, sent by the king to defeat an evil wizard who stole the king's daughters and captured the king's mystical gem. The game is similar to other beat-em-up games, in that it requires players to defeat waves of enemies in different locations using their weapons and magical abilities. However, it also incorporates some role-playing elements, such as acquiring new levels that allow players to enhance their stats and acquire new moves.

The game was originally released for the Xbox Live Arcade in 2008, and was later ported to the PS3, Windows, and macOS. In 2015, it was remastered and released for the Xbox One.