Some levels in Castle Crashers can be bypassed while a player is in a cooperative game with another player who already has beaten that level. A player may notice that, after exiting a game and reloading it, some levels will remain locked, even after completion. This is noticeable as early as the Forest Entrance level. To unlock this level permanently, Thieves' Forest must be completed. If playing with someone who has already completed Thieves' Forest, the player only needs to complete this level to unlock Forest Entrance, demonstrating that some levels can be skipped, as long as the one following it is completed. This means players can complete the game for a character, Skull, or for Insane Mode relatively quickly.