The finale scene you receive beyond the credits depends on how long it took you to clear the game. Check below for the three possible time requirements and rewards.
When the large close-up of Samus appears after the credits roll, she'll give you a thumbs-up and jump into the background before firing her weapon at the screen.
When Samus appears after the credits, her helmet will partially disappear to reveal part of her face. She'll give you a thumbs-up again before jumping into the background.
|Under 3 hours:
This time Samus' entire suit will disappear revealing her wearing a black bikini. She'll then untie her hair before jumping into the background.