Super Mario Brothers DX
At the game over screen, hold A.
Immediately hold A when a life is lost, and keep the button held until the map appears.
Note: The following trick only works on The Lost Levels. At the game over screen, hold A and press Start. The game will start with ten lives.
Note: This trick only works on a new game. Select the "Toy Box" option at the main menu, then select "Fortune Teller". Keep looking at the cards until five lives are earned. Return to the main menu and choose to play the "Original" levels. Start a new game to begin with ten lives instead of five.
Go to level 3-1 and locate the two Koopa Troopas at the end stairway. Jump on the second Troopa to trap it against the stairway. Repeatedly jump on it until the maximum of 127 lives are collected.
Begin a game in level 1-1. Locate the hidden extra life mushroom above the bush after the first pipe that you can enter. Save the game at this point. Load that file to find that you have one more life. Repeat until the desired amount of lives have been collected. Note: Depending on how many lives are desired, this procedure may require a large amount of time.
Always restart with ten lives
Save and exit the game after only having one life left. Select the "Toy Box" option at the main menu, then select "Fortune Teller". Keep looking at the cards until five lives are earned. Return to the saved game. After losing a life, the game will start over with ten lives.
Play as Luigi
At the map screen, press Select.
Boo vs. You bonus levels
Accumulate at least 100,000 points in the game. Then, select Boo as a character at the title screen.
Select Mario's form
At the "You vs. Boo" mode level selection screen, press Select to cycle Mario into his super, fire, and normal forms. Note: This also may be done in versus mode with the link cable.
Lost Levels bonus levels
Accumulate at least 300,000 points in the game. Then, select Luigi as a character at the title screen.
Japanese version of Super Mario Brothers 2
Accumulate at least 300,000 points in the Classic game without losing all lives, and without saving and restarting the game. Then a new "Super Mario Bros. For Super Players" game will be unlocked.
Successfully complete the first quest.
Successfully complete a level with a time that ends in a 1, 3, or 6.
While playing a game, press Select to switch the screen from being centered to an edge. Hold Up or Down to shift it up and down.
Reveal Yoshi egg locations in challenge mode
Locate one Yoshi egg, then go to the toy box and select Yoshi's head.
Use the "Extra lives" trick to start with at least ten lives. Then, play until reaching level 3-2. At the beginning, hit the turtle shell and follow it until it hits all the enemies. You should get at least 20,000 points and an extra life. Repeat this until reaching 300,000 points to race Boo or play the Lost Levels.