Credits
Once you beat the game or complete the game on any difficulty setting, the credits start running. Most people skip through or ignore the credits, but there's a special game hidden in the credits. Keep watching the credits until you see a message on the screen giving a special thanks to SMB3W4 and select it before it leaves the screen. This opens up a special level of the game where you play against giant size opponents. The term refers to "Super Mario Bros. 3," World 4, which was a level of the game where the brothers fought giant opponents. You can select the credits from the main menu and watch from there.
Cheat Levels
If you're in a hurry and want to get through a level quickly, then you can use a "Defend Your Castle" cheat. When you get to a spot in the game that you can't pass, pause the game. Even though the game is paused, the level keeps moving, as the time clock in the game doesn't stop. This is a glitch in the game that works to your advantage. Return to the game and check the location of the sun. Once the sun reaches the far side of the screen, the level is over. You can use this cheat on any level in the game when you find yourself stuck.
Chuck Norris
This cheat is known as either Texas Ranger mode or Chuck Norris mode. Chuck Norris was an inspiration for some of the original creators of the game, and an homage to the superstar is found in the credits. When you watch the credits, look for the special thanks message to Chuck Norris and select his name. This opens a new level in "Defend Your Castle," which is harder than the original. This cheat is only available on the "Defend Your Castle" game for the Wii, and not for the computer version.