Super Mario Bros. 3

Warp Whistles
There are three warp whistles (all originally found by Ryan L. Lawrence) in Super Mario Bros. 3. When used, they take Mario to the Warp Zone (world 9). It only takes a maximum of two whistles to get to world 8 from any other world, as using a warp whistle whilst in the Warp Zone takes Mario to world 8.

World 1-3
Crouch on the fence, and the white block with a red Koopa on top of it about two thirds of the way through the level. After a few seconds, Mario will fall through the block and be behind the level's scenery. Walk to the end of the level, where mario will go behind the black end of level scenery. Continue walking and Mario will end up in a secret toad house. Open the chest to get the whistle and exit the level.

World 1 fortress
Get the raccoon suit at the end of the first room of the fortress, then fly up on top of the roof of that platform. Walk as far as you can to the right and press up. Mario will go into a small room with a chest in the middle. Open this to get the warp whistle and clear the level.

World 2
Get the hammer item from one of the Hammer brothers towards the end of this world. Then go to the very top-right corner of the map and use the hammer. The rock to the right will smash, revealing a secret path into another part of the map. Defeat the hammer brothers in this part of the map to get the final warp whistle.

The Lost Levels in Super Mario Bros. 3

 * The lost levels in Super Mario Bros. 3 are unused, abandoned levels that were programmed into the game, but were deleted from the final version. Some of these levels feature lost enemies that are also programmed into the game. The level that sheds some light on the subject is the level that can be accessed with the Game Genie code . This code forces entry into a lost level found inside the START panel in World 1. The level seems like it was deleted from World 6 for being too short and too easy. This is generally true of all the levels, especially ones matching motifs that appear later in the game. This suggests that these may either have been in the early stages of development before being deleted from the completed game, developmental versions of in-game, final cut levels, or may have served some other purpose such as use in conjunction with development tools.

Other codes include:
 * , a lost plains stage similar to Worlds 3-9 and 5-3.
 * , a grassy, hilly stage featuring Goomba's shoe, Lakitu, a coin heaven and continuous Starman power-ups. Possibly an early version of World 7-3.
 * , an underground level with big doors and Buzzy Beetles. The layout of this level is reminiscent of World 1-5, but without the coin heaven.
 * , unused Tanooki Suit bonus rooms with castle music.
 * , an auto-scrolling underwater ice level reminiscent of World 6 with Jelectros from World 7-4 and gold Cheep-Cheeps, an unused enemy in the final game. The middle of this level consists of an island filled with Munchers.
 * , a vertical level with waterfalls and pipes.
 * , a cloud level filled with red Parabeetles and the unused, fast-moving green Parabeetles.
 * , obviously a harder version of World 1-6.
 * , another variation of the above level. No goal, cut short.
 * , an unused cloud level. May be an attempt at a nighttime cloud level.
 * , an unused level, presumably an early version of a World 7 level.

Caution: When using these codes, the pointers and enemies may load up incorrectly, or the screen may glitch all together and make the level unplayable.

Super Mario Bros. 3 Debug Mode
The Super Mario Bros. 3 Debug Mode can be accessed through the Game Genie code,.