New Super Mario Bros. Cheats
Unlockable: Play as Luigi
Beat the game and save it. Then, select the saved game and hold down both the L and R BUTTONS, then enter A. The green sporting super mario bro is unlocked.
Unlockable: Special Backgrounds
First you beat the game. Then load the saved file for that game. Go into the blue Toad house now located in World 1. In here you can purchase five different backgrounds for your lower screen. They all cost Star Coins. To get the fift background, you have to get all of the star coins in the through-out all the levels.
Toady claims to get the fifth background you must collect all star coins. This is wrong. You only need to clear a path to every mushroom hut. Finish the game and a path to a blue mushroom hut will appear in World 1. It contains the starting touchscreen theme and three additional background patterns that can be purchased for 20 star coins each. A fifth theme can be bought once you've cleared paths to the mushroom huts in every world.
Unlockable: Unlimited Toad House Items
Cleat all the levels and lettered bonus levels in the game and save it.
Hint: Extra Toad Houses
At the end of the levels, jump onto the flagpole and when the last two digits of your countdown timer are the same. For Red Houses, jump on at 11, 22, or 33. For Green Houses, jump on at 44, 55, or 66. And for Orange Houses, jump on at 77, 88, or 99.
For more power-ups, go back to World 1 and play the stages with the Red Winged Question mark blocks.
Hint: Warp to World 5
There's a warp pipe that'll instantly bring you to World 5 from the World 1-Tower. When in the hidden room with the second Star Coin, notice a small gap in the upper-right corner of the room that's never closed by the shifting blocks. You can jump into the gap to reach a hidden area with a 1-Up (smash the invisible blocks as soon as you enter the room). Shell Mario can go one further, breaking the blocks along the floor to reach the warp cannon.
Hint: Inifinte 1UPs
At the pipe right at the end of World 1-4, kick a koopa shell and it'll keep sliding back and forth between the pipe to the right and the wall to the left. If you jump every time the shell comes your way, the shell will kill the enemies that constantly appear, eventually giving you you 1UPs.
First, each time you get to a boss stage, return to world 1. Play the first stage once through, getting all the power ups but the giant mushroom (you are forced to only be super mario at the end of the level if you gat it, without the fireballs). Instead, beat it and jump on the flag pole when the last two digits of the clock are either 66, 55, or 44. This way, a toad house with extra lives will appear. Repeat this until you have many, many lives to spare.
To cheese the bosses, play through one more time (without getting the big mushroom) and end when the last two digits of the clock say 99, 88, or 77. This will make a toad house with the giant mushroom powerup appear. It will replace whatever else you already have. Finally, go to the stage with your newly equipped giant mushroom, fireballs, and lives. Play through it, but don't use your giant mushroom yet.
When you get to whatever boss you are playing, immediately activate the giant mushroom. Now you can defeat the boss just by touching him! I don't know if the big mushroom will kill all bosses, but for most bosses, this works.
Hint: Free Mushroom Houses
Instead of immediately jumping onto the flag pole at the end of a stage, take your time and watch the clock. If you hit the flag when the last two digits of your timer are the same (example: 133, 211, or 099) you'll unlock a mushroom house on your World Map. If the last two digits are 1, 2, or 3, you'll unlock a red mushroom house. If the last two digitsl are 4, 5, or 6, you'll unlock a green mushroom house. If the last two digits are 7, 8, or 9, you'll unlock an orange mushroom house.
Hint - Warp Zone Cannons
In some worlds, there are cannons you can access (usually through taking secret exits). When you enter the cannon area, there will be a large cannon in the area, and a world number written below it. If you want to warp, simply drop into the cannon and off you go! Here is a list of the known warp zones thus far:
World 5 Warp #1: Take the secret exit from the World 1 Tower.
World 5 Warp #2: Take the secret exit from Stage 2-A.
World 6 Warp: Take the secret exit from the World 3 Ghost House.
World 7 Warp: Take the secret exit from the World 4 Ghost House.
World 8 Warp: Take the secret exit from the World 5 Ghost House.