Listener: Found the first Audio Log. (10)

Notes: See "Audiophile"

Tuned In: Found 3 Audio Logs, alone or with another ODST. (10)

Notes: See "Audiophile"

All Ears: Found 15 Audio Logs, alone or with another ODST. (10)

Notes: See "Audiophile"

Audiophile: Found all Audio Logs, alone or with another ODST. (75)

Notes: Video featuring all audio log locations. Thanks ClaSSIc

Tayari Plaza: Completed Tayari Plaza on Normal, Heroic or Legendary. (30)

Notes: Unlocks the Buck character in Firefight. See "Coastal Highway"

Uplift Reserve: Completed Uplift Reserve on Normal, Heroic or Legendary. (30)

Notes: Unlocks the Dutch character in Firefight. See "Coastal Highway"

Kizingo Boulevard: Completed Kizingo Blvd. on Normal, Heroic or Legendary. (30)

Notes: Unlocks the Mickey character in Firefight. See "Coastal Highway"

ONI Alpha Site: Completed ONI Alpha Site on Normal, Heroic or Legendary. (30)

Notes: Unlocks the Alpha Site Firefight map. See "Coastal Highway"

NMPD HQ: Completed NMPD HQ on Normal, Heroic or Legendary.(30)

Notes: Unlocks the Romeo character in Firefight See "Coastal Highway"

Kikowani Station: Completed Kikowani Station on Normal, Heroic or Legendary. (30)

Notes: See "Coastal Highway"

Data Hive: Completed Data Hive on Normal, Heroic or Legendary. (50)

Notes: Unlocks the Chasm Ten Firefight map. See "Coastal Highway"

Coastal Highway: Completed Coastal Highway on Normal, Heroic or Legendary. (50)

Notes: Unlocks the Last Exit Firefight map. You get all these from story progression; you can not miss them (you can only miss them if you play easy).

Campaign Complete Normal: Completed the Campaign on Normal difficulty. (100)

Notes: See "Campaign Complete Legendary"

Campaign Complete Heroic: Completed the Campaign on Heroic difficulty. (100)

Notes: See "Campaign Complete Legendary"

Campaign Complete Legendary: Completed the Campaign on Legendary. (100)

Notes: Unlocks the Dare character in Firefight. Difficulty Achievements are Stackable.

Recommend doing your first playthrough on Legendary. Playing with a Co-op partner/s would be beneficial and Legendary on Co-op is easier than Halo 3.

Junior Detective: Found the first clue unraveling the mystery. (10)

Notes: Several people have said that the clue achievements did not unlock until they pressed and checked their Intel. People have been saying the Clue achievements are glitched but this is not the case. You simply have to play through the campaign in one play through. You can not replay a mission, change difficulty, nor join another person's game; this will disable the achievement if you do so.

You will obtain this as you start the Mission BUCK: Tayari Plaza. You cannot miss this achievement.

Gumshoe: Found the 3rd clue unraveling the mystery, alone or with another ODST. (10)

Notes: You will obtain this as you start the Mission MICKEY: Kizingo Boulevard. You cannot miss this achievement.

Super Sleuth: Found the final clue unraveling the mystery, alone or with another ODST. (10)

Notes: You will obtain this as you start the Mission BUCK: Kikowani Station. You cannot miss this achievement.

Heal Up: Found the first Medical Kiosk and healed yourself. (5)

Notes: You get this in the first mission: Prepare to Drop (aka The Rookie: Occupied City Center) during the tutorials. You have to find your first Medical Kiosk. There are multiple Medical Kiosk throughout the level.

Tourist: Accessed and downloaded the city map to your VISR. (5)

Notes: You get this in the first mission during the tutorials. Once you start your VISR Nav Data Tutorial, this will unlock. Unfortunately you can't skip the tutorial after you get the achievement.

Headcase: Finished any level with at least one Skull activated. (5)

Notes: You must activate any skull and complete a mission; you can play on any difficulty. Play with the Skull: Birthday Grunt or IWBYD (Yes secondary skulls work) activated. Just activate this on the first level 'Tayari Plaza' or any level you desire.

Trading Down: Traded weapons with a fellow character. (5)

Notes: Go up to a CPU teammate with a different weapon and press . The first time you meet an Ally CPU where you can trade weapons is in the Mission BUCK: Tayari Plaza. The 2 Allies are near the beginning of the level after you defeat the first group of enemies.

Vidmaster Challenge: Endure- In Firefight, on any mission, passed the 4th Set on 4-player Heroic LIVE co-op. (25)

Notes: Use Alpha Site. Just make sure you stay back and use Plasma pistols and Automags for quick kills. Also use the rocket on Cheifstans and in the bonus round. If you aim above the elevators and shoot as the grunts come out you will easily get the bonus lives. Click HERE and look at Vendetta's Tips on Endure.

Vidmaster Challenge: Classic- Finished any level solo on Legendary, on LIVE, with no shots fired or grenades thrown. (25)

Notes: For this achievement do the level 'Uplift Reserve'. You can drive pass all the enemies and straight to the end of the level. You can use Ghosts, Choppers, and Warthogs. You can have a passenger and Turret operator firing at enemies. This will NOT disable the achievement. What will disable the achievement is if you press the horn button.

In the beginning flip the warthog straight ahead of you and get into it. Drive counter clock-wise around the rock and once you jump off the edge continue straight. You will come to a narrow pathway where wraiths, ghosts and choppers will come up. Simply stick to the right and pass them. Once you pass them there will be a Ghost on the rock. It is up to you to use it. Drive out the tunnel and go to the left. Once you see the pond drive to your right. Get out of the vehicle and climb up the rocks (this is to avoid those turrets further up ahead). There will be a ghost waiting for you. The rest of the level is easy and needs no further explanation.

Vidmaster Challenge: Déjà vu- Completed Highway on 4-player Legendary LIVE co-op, with Iron, and no Hog or Scorpion. (25)

Notes: You must be on Legendary and have Iron on for the Rockets/Mongooses to spawn. First you must defeat the enemies in the beginning of the level and then go to the elevator. Once you are on the Highway walk straight and you will eventually find a tunnel which leads you underground. Go inside and you will find 2 Mongooses and 4 rockets each with 1000 shots. (Thanks to icypinksmurf). Now all you do is drive and use the Mongooses and rockets to protect the Elephant and kill all the enimies. You can also board a ghost and use it. Once you get to the end of the level and you must repel the attack, you can keep using the rockets and there are also 2 turrets at the top in the back of the level. This may take a few tries but it shouldn't be too time consuming.

Wraith Killer: Killed all Wraiths in Uplift Reserve. (5)

Notes: There are 6 wraiths in the level and you must kill all 6. If you are doing this in co-op, only one person can obtain this achievement. Player 1 (Host) starts with a Spartan Laser; use this to kill 5 of them, and then board and throw a grenade inside on the last one (or you can choose a different method).

Both Tubes: Got 10 Rocket kills on Kizingo Boulevard. (5)

Notes: Melee Kills with the Rocket Launcher will not count towards the achievement.

You start off with 2 rockets on this level. If you are doing Co-op, your partner will also start with 2 rockets. It is recommended to go for this achievement with at least 2 people. Take the extra Ammo from your partner(s) if you have any partners. Another way to get extra ammo is when you have 1 shot left, trade weapons with a team mate and then kill him. Pick up the rocket launcher and there should be extra ammo. When you begin the level there will be Columns with some orange lights. Continue to the next area with Columns and Orange lights (only a 10 second walk). To the left a bunch of grunts, some jackals, and a few brutes will appear. Pick a spot where they're all bunched up and shoot a rocket (You can easily get 3-6 kills in one shot). Use the rest of your rockets wisely and shoot at clusters of enemies (if you react quickly, shoot another well placed shot. There will still be quite a few enemies left grouped together).

An alternative method is to Drive the tank and have allies sit on the side and kill enemies with Rockets. This will count towards the achievement. (Thanks to Toasty411)

Laser Blaster: Got 10 Spartan Laser kills on ONI Alpha Site. (5)

Notes: You can easily get this as there are several Spartan Lasers throughout the level. But at the beginning only player 1 starts off with it on co-op. Straight ahead of you will be a wraith and lots of enemies. Aim towards the wraith and try to line up as many enemies as possible in your line of fire. You can easily get 2-5 kills (or more) in one shot and you have 5 shots in total.

Dome Inspector: Got 15 headshot kills on NMPD HQ. (5)

Notes: Obtain 15 headshots with any weapon that can get a headshot: Automag, Carbine and Sniper. Just simply use the Automag and headshot Grunts, Jackals, and Brutes with no Shields. You will get this in no time.

I Like Fire: Killed 10 enemies with the Flamethrower on Data Hive. (5)

Notes: The Flamethrower is located after the 2nd drop near the area that is frozen. It is behind a glass-like wall in a corner.

Good Samaritan: Killed no Engineers in the city at night during entire campaign, alone or with another ODST. (20)

Notes: To do this you cannot kill any Engineers (they float in the sky and give over shields to their allies). If you kill one (shown by achievement tracker) reload checkpoint/kill yourself. You will get this when you Start the Mission: Data Hive (the first mission which isn't a flashback mission).

Naughty Naughty: Killed 10 Engineers in the city at night, alone or with another ODST. (5)

Notes: Simply kill 10 engineers before you Start the Mission: Data Hive (the first mission which isn't a flashback mission). If you shoot them and they self-destruct they will count towards the achievement (I recommend charging a plasma pistol and shooting them). The Achievement tracker will tell you if it counts. Recommended to go for on second playthrough, or after you complete the game you can reload the Mission: Mombasa Streets. Search all the Sectors for them and eventually you will find them. If you can't find enough, they will eventually respawn (sometimes) if you aren't in the area. If you are still having trouble finding some, and it seems to take too long to walk around the city, then go to the Supply Cache (Green Circle). What is at the Supply Cache might you ask? Only two beautiful Mongooses.

Boom, Headshot: Got 10 automag headshot kills in any level. (5)

Notes: Get 10 automag headshots. The automag is the pistol you start out with. You can obtain this in the very first Mission: Prepared to Drop (aka The Rookie: Occupied City Center) if you want to. Grunts and Jackals take 1 head shot to kill (on any difficulty). Brutes also take 1 head shot if you take off their shields.

Stunning!: Stunned a vehicle with an overcharged plasma pistol and quickly killed the driver. (5)

Notes: Simply get a plasma pistol, charge plasma pistol and shoot the enemy vehicle, then switch to secoundary gun (Automag is recommend; go for head shot) and kill them. (Your teammate can shoot the plasma pistol and you can finish them off, or vice-versa). Uplift Reserve have lots of vehicles so I’d recommend doing it there. You will see many enemy vehicles throughout the game

Ewww, Sticky: Got 5 sticky grenade kills in any level. (5)

Notes: Sticky grenade 5 enemies. You can use Plasma grenades or Sticky Grenades. You will find many grenades in a mission, so you can choose what ever level you want to.

Dark Times: Killed 5 enemies while using VISR mode. (5)

Notes: Simply press and go into VISR mode and kill 5 enemies. You can easily obtain this in the first Mission: Prepare to Drop (aka The Rookie: Occupied City Center).

My Clothes!: Plasma Pistol Overcharged and quickly killed 10 Brutes. (5)

Notes: Preferred Method: Plasma Pistol a Brute or a Jackal with a shield and switch to the Automag and kill them (go for head shots; it takes only 1 head shot). Your teammate can shoot the plasma pistol and you can finish them off or vice-versa. Remember you must kill them quickly.

Alternative Method: Plasama Pistol a Brute or a Jackal with a Shield (make sure you are only a few feet away from them) and then Melee them. You will have to Melee the Brute several times which may take too long, and there is also the factor of being killed/injured more easily since you are in the center of the battle.

Pink and Deadly: Got 10 Needler supercombine kills on any covenant. (5)

Notes: Supercombine kills are when you unload enough needles for them to explode and kill them. Simply do this to 10 enemies. I would recommend the Mission: Tayari Plaza, Data Hive or Uplift Reserve as they have vast amount of needler ammo.

Crater: Scored over 200,000 points in Firefight on Crater. (10)

Notes: See "Last Exit"

Lost Platoon: Scored over 200,000 points in Firefight on Lost Platoon. (10)

Notes: See "Last Exit"

Rally Point: Scored over 200,000 points in Firefight on Rally Point. (10)

Notes: See "Last Exit"

Security Zone: Scored over 200,000 points in Firefight on Security Zone. (10)

Notes: See "Last Exit"

Alpha Site: Scored over 200,000 points in Firefight on Alpha Site. (10)

Notes: See "Last Exit"

Windward: Scored over 200,000 points in Firefight on Windward. (10)

Notes: See "Last Exit"

Chasm Ten: Scored over 200,000 points in Firefight on Chasm Ten. (10)

Notes: See "Last Exit"

Last Exit: Scored over 200,000 points in Firefight on Last Exit. (10)

Notes: All you have to do is score 200,000 points in firefight. In co-op the total of all the players scores counts to the achievements. It is recommended to do 4 player co-op to get points faster. You can easily achieve 200,000 points in 1-2 hours with 2 player Co-op on Easy. If you have 4 players, I would recommend doing normal; you can get 200,000 points on normal 4 player Co-op in 40 mins - 1 hour and 20 mins. If you have 4 skilled players, you can do Heroic; it will take 30-50 mins depending on the level.

Be Like Marty: In Firefight, finished a full round without killing a single enemy. (10)

Notes: To do this you CANNOT kill anyone untill all 5 waves are over and the 2nd round starts. The achievement will pop-up as Round 2 begins. If you haven't already guessed, this means you need a Co-op partner to kill all the enemies for you. Recommended on easy.