Super Mario Bros. 3

Super Mario Bros. 3 is one of the best-selling games of all time, and with good reason. It also has plenty of unused material hidden within it.

Developer Debug Leftovers
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
Game Genie code 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 (no operation) instructions, likely done just before release.

Disconnected Debug Leftovers
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 instruction or moving the Objects_HandleScrollAndUpdate label since this method would fall through into normal game code).

Unused 2P Level


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.

Object 00
Bank ID:

Object ID:

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
Bank ID:

Object ID:

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 Player's feet) and moves upward at some changing speed by peculiar logic.

Object 04
Bank ID:

Object ID:



''Note: This is not how the object actually appears in-game. Image is for reference only.''

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. 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
Bank ID:

Object ID:



''Note: This is not how the object actually appears in-game. Image is for reference only.''

Another weird sprite. The tiles that actually make up this object are no longer in the ROM, but it was supposed to use tiles. 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
Bank ID:

Object ID:

Note: This is the best fit for this object's graphics, but it may not be correct.

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
Bank ID:

Object ID:

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. The only thing I can think of is that this was going to be 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
Bank ID:

Object ID: (Mushroom),  (Fire Flower),  (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
Bank ID:

Object ID: (Single),  (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
Object ID: N/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
Bank ID:

Object ID:

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
Bank ID:

Object ID:

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

Fortress


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

Giant


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

Plains


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

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

Stage Anomalies
There are a few stages with hidden foreground pieces.

A single brick is hidden behind the waterfall in World 4-1.

A cloud appears behind the first slope in World 5-2.