As with all Metroid games, you'll receive a different ending after the credits roll depending on how long it took you to complete the game.
When "The End" appears and your total time is displayed, Samus continues to run towards the screen.
Samus leaps up out of the screen and lands with her armour still on, she then stands motionless.
|Under 3 hours:
Samus will again jump up out of the screen, but when she lands her entire suit will disappear revealing her wearing a two-piece bikini. She unties her hair and stands motionless.