Samus' basic suit, the Power Suit, is upgraded three times in the course of the game. In addition, you can collect Energy Tanks which increase the suit's available energy (basically your health).
|Power Suit||This is Samus' basic suit. Perhaps the most notable feature of this suit is the lack of the large shoulder ornaments present in all of her other suits. (These shoulder ornaments have sometimes been hypothesized to be part of the Varia Suit's ability to survive extreme temperatures, perhaps being cooling units of some sort.)
The function of the suit is to provide life-support and protection. This requires energy though and when your suit's energy reserve reaches 0 you get a Game Over. Energy is drained by enemy attacks and environmental hazards and is restored by finding Energy pickups (Small, Large and Ultra).
|Varia Suit||The first upgrade to the Power Suit, this increases the suit's shielding and allows Samus to survive in extreme heat. Collecting this also returns the large shoulder ornaments seen in other games. The Varia Suit is obtained after defeating Flaagrah, the boss of Chozo Ruins.|
|Gravity Suit||The second upgrade to the Power Suit, this further increases the shielding and allows Samus to move in liquid environments unhindered. Modifications to the visor allow her to see properly underwater. Gives Samus' suit a purplish color.|
|Phazon Suit||The third and final upgrade, this increases shielding even more, and renders Samus immune to damage from blue Phazon. This upgrade comes coupled with the Phazon Beam which can only be used on the last boss (Metroid prime) by standing in the pools of phazon spilled by it. Changes Samus' suit to a black and grey color it also gives off a nearly un-seeable aura. The Phazon Suit is obtained by defeating Omega Pirate in Phazon Mines.|
|Energy Tank||You start the game with an engery capacity of 100. Each Energy Tank you find increases that amount by 100. Energy Tanks are found all over Tallon IV and throughout the game, but are often difficult to find or reach. Finding Energy Tanks is vital to your ability to survive in the game.|