Cheat List: NES Metroid:
When playing the original NES Metroid, enter the following codes at the password screen to unlock the effects.

* Best ending with no suit: X----- --N?WO dV-Gm9 W01GMI
* Debug Mode: BOMBS_ MISSLE SCREW_ ATACK_
* Hard Mode: 999999 999999 KKKKKK KKKKKK
* Infinite missiles and health with all upgrades: NARPAS SWORD0 000000 000000
* Start with Morph Ball and Bombs: 000000 000000 4G0000 00000H
* Suitless Samus: JUSTIN BAILEY / ------ ------
* Start with Suitless Samus: 000000 000020 000000 000020
* Start on Norfair with Suitless Samus and infinite missles. No item upgrades except missles: SAMUS8 RIDLEY 444444 444444
* Start at Kraid's Lair with the Long Beam, Ice Beam, Bombs, High Jump Boots, Screw Attack, Varia, Suitless Samus, and 255 Missles: JUSTIN BAILEY ~~~~~~
* Start in Tourian, with Mother Brain defeated: Samus_ Beats_/Mother Brain_ (_=space)

Unlockable: All Zero Mission Endings:
To open up the various game endings fulfill these requirements.

* Samus in shorts, at a bar: Complete the game in under two hours on Normal with 100%.
* Samus in shorts, in a city: Complete the game in over two hours on Normal or Hard with 100%.
* Samus on a rock: Complete the game on Easy, or complete the game in over four hours in Normal or Hard with more than 15%.
* Samus in a blue jumpsuit: Complete the game in under two hours on Normal or Hard with more than 15%.
* Samus in shorts, looking over a city: Complete the game in under two hours on Hard with 100%.
* Samus in shorts, looking out a window: Complete the game on Normal with less than 15%.
* Samus with a close up on her face without armor: Complete the game on Hard with less than 15%.
* Samus without helmet, looking at a sunset: Complete the game in three hours on Normal or Hard with more than 15%.

Unlockable: Ending Image Galleries:
These image galleries are available in the options menu.

* Metroid Fusion Ending Images: Link Metroid: Zero Mission with Metroid Fusion via a Game Boy Advance Game Link cable.
* Metroid: Zero Mission Ending Images: Complete Zero Mission to unlock one ending image. Run through the game eight times to fill the gallery with all eight ending pictures.

Unlockable: Original NES Metroid Game:
Complete one run through Metroid: Zero Mission.

Unlockable: Sound Test Mode:
Complete one run through Metroid: Zero Mission.

Unlockable: Time Attack Mode:
Beat Zero Mission once through and begin a new game with the completed save file. View the timer on the map screen.

Blind Spot:
When battling Ridley, go to the far end of the platform and jump into the lava; next, jump and grab the platform. Ridley can't reach you and you can fire missiles at him.