Metroid II: Return of Samus

Metroid II: Return of Samus
Developer: Nintendo R&D1 Publisher: Nintendo Platform: Game Boy Released in JP: January 21, 1992 Released in US: November 1991 Released in EU: May 21, 1992 This game has unused graphics. This game has debugging material. This game has revisional differences.

Metroid II: Return of Samus is best known as "that game between the first one and Super Metroid".

Debug Mode

GameShark code 0101A0D0 or Game Genie code A02-52B-193 will enable some debugging features.

During the game, on pause you can:

• Adjust what items you have. Select a bit with Left / Right and press A to toggle the highlighted flag:
  • flag 0: Bombs
  • flag 1: High Jump Boots
  • flag 2: Screw Attack
  • flag 3: Space Jump
  • flag 4: Spring Ball
  • flag 5: Spider Ball
  • flag 6: Varia Suit
  • flag 7: Never used in game
• You can also change what weapon you're using by pressing Up / Down:
  • 00: Standard
  • 01: Ice Beam
  • 02: Wave Beam
  • 03: Spazer Beam
  • 04: Plasma Beam
  • 07: Bomb Beam (Unused. When the bullet hits a wall it leaves a bomb)
  • 08: Missiles
• Press Select to save current progress without any indications. Just one condition: the character must not be in the air. This causes the save text to be loaded over the enemy graphics when you start again, which can be fixed by moving to another area.
• Hold B and press Left / Right to adjust the number of energy tanks you have. Removing tanks doesn't produce a visible effect until the game is resumed.
• Hold B and press Up / Down to adjust your missile counter by 10 per button press after you resume the game. There are three internal missile counters in this game: the maximim possible value, and two current values of actually posessed missiles (when you change the first one, the second one will be automatically adjusted to the same value, for "counting" effect). This option does not decrease the maximum value counter, the only value is decreased here is the current missile value counter. When increasing, the maximum value + 10 is reloaded into the current value counter, both counters will have the same value until you decrease, so we can see some kind of "weird" behaviour here because of that. All counters are 4-digit decimal counters, but game only displays lower 3 digits, however, you still can have as many as 9999 missiles, then warp to zero again.
• Hold A + B and press Left / Right to adjust the number of remaining metroids.

During the game, in transitions between locations:

• Hold Select + B to warp directly to the final boss.

(Source: BSFree (Kong K. Rool), nensondubois, Lordgenome)

Unused Screens

There are two more system handlers with the same structure as the Game Over screen. One displays message "GAME SAVED", the other "GAME CLEARED". It is unknown, when they should be displayed, but most likely one is for saving during the game, the other is for clearing the state slot at the title screen. Both are unused in the final version.

To see any of them, use the Game Genie code ZEKAIZAE for the "saved" screen or AOKAIZAA for the "cleared" screen respectively.

The save screen, however uses wrong tile data loading offset and size, so text here is unreadable. But you can use two more codes AEVUNZEA+AONLXXAP to fix it.

Unused Tiles

Two unused tiles exist in the ROM: a small alien statue (appears three times in the ROM) and an alternate save point sprite.

The numbers 3 and 8 are part of the font set used in the game's credits. The Metroid home planet (and the planet this game takes place on) is SR388, so those tiles might have been meant for an unused intro or epilogue text like the ones in the first game.

Inaccessible Content

In the second room of the game, if the player stands partway down the hill at the start of the room, a rhythmic percussive sound can be heard.

If the ROM is edited to allow us to pass through the floor, we can see that there are several "Rock Icicle" enemies (with incorrect graphics) placed offscreen (in fact, completely outside of the bounds of the room, if the room boundary is not disabled as it was in this video).

These enemies are actually placed here accidentally; the game apparently continues loading map data some distance beyond the actual defined limits of whatever room is loaded, and in this case it begins reading from the data for another room later in the game (though with the wrong tileset loaded), which includes the Rock Icicles. This glitch presumably occurs throughout the entire game, but its results are usually undetectable, since the game's camera always stops scrolling before this 'outside' data would show up on screen, and very few things in the game make sound except when Samus is interacting with them (with Rock Icicle enemies being one of the exceptions).

So, technically, an instance of this "content" can be accessed normally when visiting the room that this accidentally-read room data is meant to be found in; but the specific instances of the enemies that the game accidentally creates in this starting room by reading that data at the wrong time will always be stuck unreachable just off-camera.

Virtual Console Changes

The 3DS version has a very subtle change on the title screen. Every 1,024 frames, the screen rapidly blinks 3 times in the 3DS version (as opposed to 4 times in the Game Boy version), though the blinking rate stayed the same. This change may have been made to reduce the risk of seizures, though it is dubious as to how much this helps.