Metroid Prime

Normal ending:
Finish the game and reacch 74&#37 or less completion

Different ending:
Finish the and reach 75&#37 to 99&#37 completion

Best ending:
Finish the game with a 100&#37 completion

Samus without suit in classic Metroid ending:
Finish the classic Metroid game less than 2 hours

Unlock Image Gallery 1 option
Finish 50&#37 completion of the research and creature data scans

Unlock Image Gallery 2 option
Finish 100&#37 of the research and creature data scans

Unlock Image Gallery 3 option
Finish the game on hard mode

Unlock Image Gallery 4 option
Find 100&#37 of all power-ups

Unlock Hard mode
Finish the game with a 100&#37 completion

Fire missiles faster
With the first gun equipped, rapidly hit Y + A, then
hit Y again when the gun switch back to beam weapon mode

Unlimited health
While playing the game on any level, press - L,R,L,R,L,B,Y,Z
(This cheat is not tested!)

Classic NES version of Metroid and Samus' Metroid Fusion costume:
Note: You need Metroid Fusion and the GBA link cable to do this.
Finish Metroid Fusion and save the game after connect both games
with the link cable.