Don't kill any engineers throughout the entire campaign
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