Full list of all 47 Halo 3: ODST achievements worth 1,000 gamerscore. It takes around 25-30 hours to unlock all of the achievements on Xbox 360.
Completed Kikowani Station on Normal, Heroic, or Legendary.
Completed NMPD HQ and unlocked the Romeo character in Firefight.
Completed ONI Alpha Site and unlocked the Alpha Site Firefight mission.
Completed Kizingo Blvd. and unlocked the Mickey character in Firefight.
Completed Uplift Reserve and unlocked the Dutch character in Firefight.
Traded weapons with a fellow character.
Finished any level with at least one Skull activated.
Completed Tayari Plaza and unlocked the Buck character in Firefight.
Found the first clue unraveling the mystery.
Scored over 200,000 points in Firefight on Last Exit.
Got 5 sticky grenade kills in any level.
Got 10 Needler supercombine kills on any covenant.
Got 10 automag headshot kills in any level.
Accessed and downloaded the city map to your VISR.
Killed 5 enemies while using VISR mode.
Found the first Medical Kiosk and healed yourself.
Stun a vehicle with an overcharged plasma pistol and quickly kill the driver.
Plasma Pistol Overcharge and quickly kill 10 Brutes.
Complete Data Hive on Normal, Heroic, or Legendary to unlock a new Firefight mission.
Complete Coastal Highway on Normal, Heroic, or Legendary to unlock a new Firefight mission.
Complete the Campaign on Normal difficulty.
Complete the Campaign on Heroic difficulty.
Complete the Campaign on Legendary to unlock a new Firefight character.
Find the 3rd clue unraveling the mystery, alone or with another ODST.
Find the final clue unraveling the mystery, alone or with another ODST.
Kill all Wraiths in Uplift Reserve.
Get 10 Rocket kills on Kizingo Boulevard.
Get 10 Spartan Laser kills on ONI Alpha Site.
Get 15 headshot kills on NMPD HQ.
Kill 10 enemies with the Flamethrower on Data Hive.
Killing things that are new and different is bad, alone or with another ODST.
Killing things that are new and different is good, alone or with another ODST.
Find the first Audio Log.
Find 3 Audio Logs, alone or with another ODST.
Find 15 Audio Logs, alone or with another ODST.
Find all Audio Logs, alone or with another ODST.
In Firefight, finish a full round without killing a single enemy.
Score over 200,000 points in Firefight on Crater.
Score over 200,000 points in Firefight on Lost Platoon.
Score over 200,000 points in Firefight on Rally Point.
Score over 200,000 points in Firefight on Security Zone.
Score over 200,000 points in Firefight on Alpha Site.
Score over 200,000 points in Firefight on Windward.
Score over 200,000 points in Firefight on Chasm Ten.
Finish any level solo on Legendary, on LIVE, with no shots fired or grenades thrown.
In Firefight, on any mission, pass the 4th Set on 4-player Heroic LIVE co-op.
Complete Highway on 4-player Legendary LIVE co-op, with Iron, and no 'Hog or Scorpion.