Complete the indicated task in Campaign mode to unlock the corresponding armor part in multi-player mode.
Elite Ascetic Body: Earn the "Up Close and Personal" achievement.
Elite Ascetic Head: Earn the "Steppin' Razor" achievement.
Elite Ascetic Shoulders: Earn the "Overkill" achievement.
Elite Commando Body: Earn the "Triple Kill" achievement.
Elite Commando Head: Earn the "Overkill" achievement.
Elite Commando Shoulders: Earn the "Killing Frenzy" achievement.
Elite Flight Body: Complete "Tsavo Highway" under the Heroic or Legendary difficulty.
Elite Flight Head: Complete Campaign mode under the Heroic difficulty.
Elite Flight Shoulders: Complete "The Ark" under the Heroic or higher difficulty.
Hayabusa Chest: Collect six hidden skulls.
Hayabusa Helmet: Collect thirteen hidden skulls.
Hayabusa Shoulders: Collect nine hidden skulls.
Recon Armor: Earn all seven "Vidmaster" achievements (four from Halo 3 and three during the launch of Halo 3: ODST).
Spartan EOD Body: Complete "Tsavo Highway" under the Legendary difficulty.
Spartan EOD Head: Complete Campaign mode under the Legendary difficulty.
Spartan EOD Shoulders: Complete "The Ark" under the Legendary difficulty.
Spartan EVA Body: Complete "Tsavo Highway" under the Normal or higher difficulty.
Spartan EVA Head: Complete Campaign mode under the Normal or higher difficulty.
Spartan EVA Shoulders: Complete "The Ark" under the Normal or higher difficulty.
Spartan Mark V Head: Earn the "UNSC Spartan" achievement.
Spartan ODST Head: Earn the "Spartan Graduate" achievement.
Spartan Rogue Head: Earn the "Spartan Officer" achievement.
Spartan Scout Body: Earn the "Too Close to the Sun" achievement.
Spartan Scout Head: Earn the "Used Car Salesman" achievement.
Spartan Scout Shoulders: Earn the "Mongoose Mowdown" achievement.
Spartan Security Head: Earn 1,000 Gamerscore points.
Spartan Security Shoulders: Earn the "Marathon Man" achievement in the Campaign Meta-game. Alternately, unlock at least 39 achievements.
Enjoy!