Developer Debug Leftovers Edit

There are some leftover debug routines in the game, but none can be accessed without cheat devices or hacking.

Level Select and Debug Menu/Mode Edit

Game Genie code KKKZSPIU activates a level select and debug mode.

On the title screen:

  • Press Up or Down to select a world to start on.
  • Press A to increase the number of lives by 5 (a tile will change each time you press the button).
  • A + B + Down on Controller 2 warps you to the Princess' chamber at the end of the game.
  • A + B + Right warps you straight to the final curtain.

When you start a game, your item box will be filled with one of every item plus an extra Warp Whistle, and the remaining slots will be filled with P-Wings. During gameplay:

  • Press Select on Controller 1 to cycle through all of Mario's forms.
  • A / B + Select gives Mario a Kuribo's Shoe (it may look messed-up in some levels, but will otherwise work fine).

Additionally, you'll have infinite time – it will still tick, but Mario won't die once it runs out.

The menu shown in the picture was found elsewhere in the ROM and hacked into the title screen; it doesn't appear if you use the Game Genie code by itself. Apply this IPS patch to a Super Mario Bros. 3 ROM to see it for yourself.

Originally, it appears that this menu would have been accessible from the "1 PLAYER" / "2 PLAYER" selection menu if player 2 was holding A + B. It is also possible that this served some other purpose, but the above menu would be the most likely candidate. See Disassembly source for PRG bank #24, search for "Title_Do1P2PMenu:" Interestingly, the button check is still there but the action it was supposed to perform was overwritten with a series of NOP (no operation) instructions, likely done just before release.

(Source: menu found by BMF54123; code created by David Wonn; disassembly by Southbird)

Disconnected Debug Leftovers Edit

Even if you enable the debug mode above, there are a couple of leftover routines that remain inaccessible. These routines do not seem to pay attention to the aforementioned debug flag, so either the check is simply lost to time or these routines were hardwired to always work. The latter would make sense why they are disconnected from the source.

  • Free Movement Mode - Unclear how this would be accessed, but would allow you to use the D-Pad to move around the level (see disassembly source for PRG bank #0, search for "$C3EA").
  • Toggled Invincibility - Pressing Select would toggle whether you were completely invulnerable (see disassembly source for PRG bank #0, search for "$C91B"; this behavior could be easily restored by retargeting the JMP instruction or moving the Objects_HandleScrollAndUpdate label since this method would fall through into normal game code).

(Source: Southbird)

Unused 2P Level Edit

Unused 2P bonus game

A fourth 2P level, which has a large arc of coins and uses an otherwise unused block graphic. When a coin is collected, an incorrect tile appears in its place. There is in fact code related to this level that instigates a timer which expires and then decides that Mario lost the match. Presumably, the player who collected the most coins would win, but the code that would handle this isn't in the ROM.

Unused 2P Respawn Feature Edit

Super Mario Bros. 3 - Unused feature, 2P Vs

Super Mario Bros. 3 - Unused feature, 2P Vs. Respawn

In a 2P Vs. match, there is unused game code which causes a player to respawn when they die. They will respawn flashing and invincible until the player moves them. This behavior can be restored using Game Genie code ATUZPKOZ...which as a side effect also breaks logic for exiting after enough points have been earned.

Unused Objects Edit

(Additional information: Southbird)

Object 00 Edit

Bank ID?? Object ID00 It has code that makes it move (up to a certain speed) based on player input when the player is "touching" it. What purpose this may have ever served is unclear. It may have just been used to test out collision.

Object 02 Edit

Bank ID?? Object ID02 This one is destroyed by its initialization routine if the player is not standing on two of the same tile , otherwise it starts at a vertical height matching the player +32 (roughly at the player's feet) and moves upward at some changing speed by peculiar logic.

Object 04 Edit

Bank ID00 Object ID04

A very odd object. The tiles that actually make up this object are no longer in the ROM, but it was supposed to use tiles B0-BF. It faces the player upon initialization. If Mario/Luigi collides with this object, it will stick to him like a Micro-Goomba and will never come off, but it doesn't hinder his movement. It can be killed with a Koopa shell or Hammer.

Object 05 Edit

Bank ID00 Object ID05

Another weird sprite. The tiles that actually make up this object are no longer in the ROM, but it was supposed to use tiles A0-A7. This object walks around like a normal enemy. At a certain point in its walk cycle, it will jump up to Mario/Luigi's Y position and then fall back down.

Interestingly, walking into it will bounce Mario/Luigi in the opposite direction. The only way to get damaged by this object is to let it fall on you. It can be destroyed with a Koopa shell or Hammer.

Object 0A Edit

Bank ID00 Object ID0A

A simple stationary object that can be "pushed" by Mario/Luigi. Its collision detection doesn't seem to be complete, though, since it can be pushed into walls.

Object 1C Edit

Bank ID?? Object ID1C Probably the maybe most perplexing object, this causes something to fly off towards the player, out into the sky. And where it started, a mushroom is glides along. This might have been like one of those bushes in SMW where you run by them and a mushroom pops out, though the functionality is not nearly complete enough to be used that way.

Card Objects Edit

Bank ID00 Object ID21 (Mushroom), 22 (Fire Flower), 23 (Star)

Stationary object versions of the cards found at the end of each level! Collecting them will add the appropriate card to your inventory, but there's nothing in this object's code to handle when the card collected is the third card.

Getting to the goal with three of the same card won't trigger the 1-Up bonus. You still have to get the appropriate third card from the goal.

Peculiarly, this object calls a subroutine coined "Object_MoveAndReboundOffWall", (which would be a great function for just about every ground troop in the game!), but only this object actually calls it. But the object never moves.

Gold Cheep-Cheep Edit

Bank ID00 Object ID88 (Single), D2 (Trio)

This Cheep-Cheep variant only appears in the seventh unused level. In that level, they always show up in groups of three (though sprite overload often keeps at least one from appearing), but a single enemy version is in the code.

It swims across the screen in a strange wavy pattern and is considerably faster than the standard red or green varieties.

Green Para-Beetle Edit

Object IDN/A

This can only be spawned with the Para-Beetle Swarm object (see below). It flies faster than the Red Para-Beetle, but otherwise there's no difference between the two.

Bouncing Object Edit

Bank ID?? Object IDB3 A peculiar object that basically behaves similar to a Spiny Egg, but has glitched graphics. It can also curiously be "bounced" by a bounce block to turn around. Purpose unknown, maybe it was a rolling spike ball or something of that sort?

Para-Beetle Swarm Edit

Bank ID00 Object IDB7 A control object that will spawn Green and Red Para-Beetles on the left and right sides of the screen. It's used in the ninth and tenth unused levels.

Unused Level Palettes Edit

Some level types have unused palettes. Not many, though.

Fortress Edit

Fortress palette #2 is a green version of the standard fortress color scheme.

Giant Edit

Giant stage palette #2 uses shades of gray with blue water.

Plains Edit

Plains palette #1, featuring a sky with a pinkish hue.

Palette 2 (Used) Palette 6 (Unused)
Palette 2
Palette 1

Palette #6 is nearly identical to the used Palette #2. The only difference is that the blue rectangles are blue-green.