Don't kill any engineers throughout the entire campaign
You get by not killing any engineers through the whole game.
beat the game
You unlock the odst armor by unlocking the UNSC SPARTAN achievement
Unlock Halo 3:ODST's Campaign Complete Achievement. Once you beat the ODST campaign, visit Halo Waypoint on the dashboard to unlock the item.
In order to get the achievement "Good Samaritan" in Halo 3: ODST, you mustn't kill any engineers.
1:Bungie gives it to you2:You get every vidmaster achievement in halo 3 and odst
You can get 43 achievements offline on halo 3 im not sure on odst.
The Vidmaster Challenge is an Achievement that you have to unlock so you can get Recon Armor when Halo 3: ODST comes out.
You have to get the spartan graduate achievement by playing on Xbox Live
In Halo 3, you play as the Master Chief, the last surviving super-soldier of the Spartan II group. In Halo 3: ODST, you play as an ODST instead of the Master Chief. There are also different weapons in ODST.
in HALO 3 you are a Spartan and in HALO 3 ODST you are a Orbital Drop Strike Trooper (ODST)
Just beat all the levels on normal difficulty
Halo 3 ODST will be released on September 22
Yes you can get the mongoose on Halo ODST