Super Mario Bros. DX Cheats (GameBoy)

At the Map, press Select. Press Select again to revert back to Mario.

Beat the first quest.

Get a minimum of 100,000 points, than at the Title screen, select Boo.

At the Game Over screen, hold A to continue.

Perform the following actions in any order:

  Clear world 8-4 (2 pics) 
  Get fireworks after a level 
  Find a hidden 1-up 
  Find a bean stalk 
  Kill a Goomba 
  Kill a squid thing 
  Kill Latiku (guy who throws Spinys) 
  Kill a fish 
  Kill a Hammer Bro 
  Kill a bullet guy 
  Kill a Koopa Troopa (any) 
  Kill a beatle guy 
  Kill 4 Bowsers

Beat Classic game twice without warping.

Get a minimum score of 300,000 points, then at the Title screen, select Luigi.