Hold Start + B + X for two to three seconds during game play.
Classic Metroid game:
Note: This trick requires Metroid Fusion and the Game Boy Advance and a link cable. Successfully complete Metroid Fusion and save the game. Connect both games with the link cable to unlock the classic NES version of Metroid.
Metroid Fusion costume:
Note: This trick requires Metroid Fusion and the Game Boy Advance and a link cable. Successfully complete Metroid Prime and save the game. Connect both games with the link cable to unlock Samus' Metroid Fusion costume.
Image Gallery 1 option:
Complete 50% of the research and creature data scans.
Image Gallery 2 option:
Complete 100% of the research and creature data scans.
Image Gallery 3 option:
Successfully complete the game under the hard difficulty setting.
Image Gallery 4 option:
Find 100% of all power-ups. Note: This does not include the Log Book.
Information in this section was contributed by Preps Always Suk.
Note: The last picture in this gallery is that of Samus without her suit in 3D.
Hard mode:
Successfully complete the game to unlock hard mode.
Alternate ending sequences:
Finish the game with a 74% or less completion percentage for the normal ending sequence. Finish the game with a 75% to 99% completion percentage to view an alternate ending sequence. Finish the game with a 100% completion percentage to view the best ending sequence.
Hint: Fire missiles faster:
With the first gun equipped, rapidly press Y + A. As soon as the missile fires, the gun will switch back to beam weapon mode, but when you press Y again, it fires another missile. This can take down enemies in a shorter time, preventing them from having more attacks on you.
Hint: Chozo Ruins: Kill birds:
When you enter the Chozo Ruins, aim your gun skywards. You will see birds flying. Shoot the birds and they will explode, with feathers all over the place.
Hint: Chozo Ruins: Wave Buster:
The Wave Buster can be found at the Tower Of Light in the Chozo Ruins. Climb up the as far as you can, then scan the pillars to learn that they can be destroyed. It takes three missiles to destroy one pillar. There are four pillars on each level. After you lower the temple, keep jumping and destroying the pillars until you reach the top to find the Wave Buster.
Hint: Magmoor: Ice Spreader:
The Ice Spreader is difficult to find. It is in a room called the Shore Tunnel in Magmoor that has a glass case. Use the Power Bombs in the glass tube. The tube will shatter, and the Ice Spreader is directly below.
Hint: Magmoor Caverns: Avoid streams of fire:
Shoot the little objects that shoot out the fire with the Ice Spreader. This freezes them and prevents them from shooting the fire.