to get gumshoe you need to get 3 (i think) clues which are the yellow things you have to find to complete the game
You unlock the odst armor by unlocking the UNSC SPARTAN achievement
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.
Unlock Halo 3:ODST's Campaign Complete Achievement. Once you beat the ODST campaign, visit Halo Waypoint on the dashboard to unlock the item.
The Vidmaster Challenge is an Achievement that you have to unlock so you can get Recon Armor when Halo 3: ODST comes out.
in HALO 3 you are a Spartan and in HALO 3 ODST you are a Orbital Drop Strike Trooper (ODST)
You have to get the spartan graduate achievement by playing on Xbox Live
I would say Halo 3 ODST
Halo 3 ODST is not for PC but Halo 1 and maybe Halo 2-3 are
Halo 3: ODST is the newest of the two, but not the newest Halo game.
halo 3 odst, unlike halo 3, has no matchmaking, sorry