Suit upgrades enhance Samus's defensive capabilities and provide resistance to environmental hazards. These are crucial for surviving the harsh environments of Zebes.
- Varia Suit: Reduces all damage taken by half and provides immunity to extreme heat (e.g., in Kraid's Lair and Norfair).
- Gravity Suit: Further reduces damage, provides full mobility in water and lava, and grants immunity to lava damage. Essential for exploring submerged areas and lava pits without penalty.
Both the Varia Suit and Gravity Suit are permanent upgrades that stack their defensive benefits. The Gravity Suit essentially replaces the Varia Suit's environmental protection with a superior version while retaining the damage reduction. These suits are vital for progression and significantly increase Samus's survivability against powerful enemies and environmental threats.