EASTER EGGS

Super Mario Brothers - Nintendo Entertainment System

Continue on same stage
To do this, once you hit game over and have lost all lives for Mario or Luigi or both, hold A+B and then press Start at the Game Over screen.
Continue Where You Left Off
To continue the game from where you left off when you ran out of lives just hold down A and START when you see the screen that asks how many players you want to select.

 

Super Mario RPG - Super Nintendo Entertainment System

Getting the Super Jacket
To get the Super Suit, you must perform 100 consecutive Super Jumps on an enemy in battle. After you do that, talk to the dog in Monstro Town that counts your jumps to receive the Super Suit.
Obtaining the Attack Scarf
To get the Attack Scarf accessory, you must perform 30 consecutive Super Jumps in battle. After you do that, talk to the dog in Monstro Town that counts the number of times you jumped, and it'll give you the Attack Scarf if you made it over 30.

 

Super Mario Kart - Super Nintendo Entertainment System

Extra Credits
If you finish three races in the same place, you'll earn an extra continue.
Getting More Levels
In two-player race, move to the cup list and press:
L,R,L,R,L,L,R,R,A