Cheat
The closest thing to a cheat on "Castle Crashers" occurs on the Full Moon level. Start the level and then quit to the map screen or exit the entire game. When you resume play, the game will indicate you have cleared the Full Moon level.
Characters
The game includes more than 20 hidden characters you can unlock by accomplishing certain tasks. For example, beating the game with the Orange Knight unlocks the Red Dragon Knight. Beating the game with the Blue Knight unlocks the Gear Knight. Beating the game with the Red Knight unlocks the Skeleton. Beating the game with the Green Knight unlocks the Royal Guard. Completing certain areas of the game or defeating difficult bosses will also unlock characters such as the Thief, the Eskimo, the Fencer and the Ninja.
Animal Orbs
Throughout the game, you can find and unlock more than 20 different Animal Orbs, with each one causing the designated animal to float next to you and provide special advantages. Traveling to the Industrial Castle and defeating the large knight will earn you the Cardinal Orb. You'll find the Frogglet Orb buried among the first graves in the Marsh. Killing Pipistrello earns the Bitey Bat Orb. You can purchase the Monkeyface Orb at the Church store. Other Animal Orbs include the Bipolar Bear, the Chicken, the Piggy and the Zebra.
Items
The game includes nine items you must collect to advance: binoculars, boomerang, bow and arrow, compass, horn, key weapon, spade, steering wheel and treasure map. You'll need to use the Cardinal Animal Orb to find two of the items. In the Thief Forest, locate the tree with the owl, and the cardinal will find the boomerang for you. On the Full Moon level, travel the mountain path until you reach the second hut, at which point the cardinal will find the key weapon.
Trophies
The game also includes 13 achievement trophies awarded for successfully completing specific tasks. Collecting all the animal orbs wins you the Animal Handler award, one of nine bronze trophies in the game. The Conscientious Objector, one of three silver trophies, requires you to complete the Home Castle through the Barbarian Boss areas without attacking a single foe. To win the You Are Insane achievement, the lone gold trophy, you must defeat the game on Insane difficulty, which only becomes available after completing the game.