Like many other Metroid games, Metroid Prime features different endings, although as a change in form, the endings in Metroid Prime are based on item collection percentage versus time completed. Any player who gets 75% or more items will unlock the “good” ending, showing Samus without her helmet. For players who achieve 100% item completion, a special post-credit scene awaits. Be warned of spoilers!
Secret Ending (Spoilers!)
100% Maps | Missile Expansions | Missile Expansions (by Area) | Energy Tanks | Power Bomb Expansions | Artifact Locations | Missable Scans | Pirate Data | Chozo Lore | Creatures | Research | Boss Guide | Beam Combos | Extras Gallery | Endings