In Castle Crashers, players control knights tasked with defeating waves of enemies using a combination of weapons and magical abilities, while also leveling up to enhance their stats and unlock new moves. The gameplay is reminiscent of classic side-scrolling beat-em-ups, with a strong emphasis on cooperative multiplayer, supporting up to four players both locally and online.

The storyline of Castle Crashers revolves around a king's quest to rescue his kidnapped daughters and recover a stolen mystical gem from an evil wizard. Players navigate through various colorful environments, battling foes and bosses along the way.

Castle Crashers stands out with its distinctive hand-drawn art style, which is a hallmark of The Behemoth, and its engaging multiplayer experience that encourages teamwork and strategy among players.