Be Like Marty

In Firefight, finished a full round without killing a single enemy.

Audiophile

Found all Audio Logs, alone or with another ODST.

Good Samaritan

Killed no Engineers in the city at night during entire campaign, alone or with another ODST.

Super Sleuth

Found the final clue unraveling the mystery, alone or with another ODST.

All Ears

Found 15 Audio Logs, alone or with another ODST.

Dome Inspector

Got 15 headshot kills on NMPD HQ.

Laser Blaster

Got 10 Spartan Laser kills on ONI Alpha Site.

Both Tubes

Got 10 Rocket kills on Kizingo Boulevard.

Headcase

Finished any level with at least one Skull activated.

My Clothes!

Plasma Pistol Overcharged and quickly killed 10 Brutes.

Stunning!

Stunned a vehicle with an overcharged plasma pistol and quickly killed the driver.

Wraith Killer

Killed all Wraiths in Uplift Reserve.

Campaign Complete: Normal

Completed the Campaign on Normal difficulty.

Coastal Highway

Completed Coastal Highway and unlocked the Last Exit Firefight mission.

I Like Fire

Killed 10 enemies with the Flamethrower on Data Hive.

Data Hive

Completed Data Hive and unlocked the Chasm Ten Firefight mission.

Kikowani Station

Completed Kikowani Station on Normal, Heroic, or Legendary.

NMPD HQ

Completed NMPD HQ and unlocked the Romeo character in Firefight.

ONI Alpha Site

Completed ONI Alpha Site and unlocked the Alpha Site Firefight mission.

Trading Down

Traded weapons with a fellow character.

Kizingo Boulevard

Completed Kizingo Blvd. and unlocked the Mickey character in Firefight.

Gumshoe

Found the 3rd clue unraveling the mystery, alone or with another ODST.

Tuned In

Found 3 Audio Logs, alone or with another ODST.

Uplift Reserve

Completed Uplift Reserve and unlocked the Dutch character in Firefight.

Pink and Deadly

Got 10 Needler supercombine kills on any covenant.

Ewww, Sticky

Got 5 sticky grenade kills in any level.

Listener

Found the first Audio Log.

Tayari Plaza

Completed Tayari Plaza and unlocked the Buck character in Firefight.

Boom, Headshot

Got 10 automag headshot kills in any level.

Junior Detective

Found the first clue unraveling the mystery.

Tourist

Accessed and downloaded the city map to your VISR.

Dark Times

Killed 5 enemies while using VISR mode.

Heal Up

Found the first Medical Kiosk and healed yourself.