Successfully complete the game to unlock the Insane difficulty.
Successfully complete the indicated task to unlock the corresponding skin in Multiplayer mode:
Successfully complete Campaign mode on the Insane difficulty to unlock a Gamerpic of Marcus. Get the "Seriously 2.0" achievement to unlock another Gamerpic of Marcus. Get the "Friends With Benefits" achievement to unlock a Gamerpic of Marcus and Dom. With the Collector's Edition of the game, insert the bonus disc, and go to "Gamer Pictures" to unlock both sets. One set has COG and the other has Locust.
When the "Gears Of War: Press Start" screen appears, do not press Start. Allow the game to idle for a few minutes, and a bonus video will begin to play.
Successfully complete the game, and allow the credits to end to view a secret message.
The 41 Collectibles can be found at the following locations:
Act 1: Tip Of The Spear
Chapter 1: Welcome To Delta
Collectible 01: The Eagle Newspaper
When the chapter begins, make sure to select the "Training" option. Immediately after you begin, go down the alley, and look on the ground for The Eagle Newspaper; it is in the middle of the street.
Collectible 02: Ambulance Driver's Log
Once you drop down the ladder at the end of the training area, go right, and enter the garage to find the Ambulance Driver's Log.
Chapter 2: Desperation
Collectible 03: Doctor's Journal
After your first encounter with the Locusts in the hospital, you will be in a long room overlooking the floor below you. Go to the left of the room and into a small adjacent room to find the Doctor's Journal.
Collectible 04: Jacinto Medical Center File
A few rooms ahead you will find a large, enclosed reception desk in the center of the room. Check the floor inside to find the Jacinto Medical Center File.
Collectible 05: COG Letterhead
Right beside the cafeteria is a small room with a desk and a computer. Inside this room is the COG Letterhead.
Collectible 06: COG Proclamation
The COG Proclamation is on the second floor of the hospital's lobby, near some ammo just as you enter the room.
Collectible 07: COG Tags - Private Dylan Murphy
As soon as you exit the hospital, turn right to find the tags behind a pillar.
Chapter 3: Rolling Thunder
Collectible 08: Grindlift Spec Sheet
The Grindlift Spec Sheet is right behind you as you start, on the wall.
Collectible 09: Ammo Requisition Form
When you get off the rig to defend Dizzy, check to the left of the rig. It is near some bushes and ammo.
Chapter 5: Roadblocks
Collectible 10: Jacinto Sentinel Newspaper
In the first building you enter in this chapter, check upstairs. The Jacinto Sentinel Newspaper is near some grenades.
Collectible 11: Memorial Inscription
After getting rid of the Tickers, check the wall of the war memorial to find the Memorial Inscription.
Collectible 12: Landown Delivery Driver's Note
This Collectible can be found on the floor at the back of the Imulsion station.
Collectible 13: COG Tags - Private Samuel Lee
About half way through the tunnel, your way is blocked by wrecked cars. Before you go up the short set of steps that bring you to these cars, check to the left to find a room with the tags inside.
Act 2: Denizens
Chapter 2: Indigenous Creatures
Collectible 14: Gear Journal
When you find the second Rockworm, go left, and cut through the vines. You will find a Grindlift, some ammo, and the journal here.
Collectible 15: Kantus Scroll
After you reach the top of the spire and kill the Reaver that appears, you can find the Kantus Scroll behind the Troika at the back of the platform.
Chapter 3: Disturbing Revelations
Collectible 16: Locust Emblem
After your first encounter in this chapter with Drones, Wretches, and Kantus, go through the doors to find the Locust Emblem near some ammo.
Chapter 4: Sinking Feeling
Collectible 17: Ilima Help Wanted Ad
Go up the path and to the right of the Bloodmounts. It is on the overlook that faces the snipers, near a Gorgon pistol.
Collectible 18: COG Tags - Hank Bissell
On your way out, shortly after Cole saves you, the tags can be found just inside the building.
Chapter 5: Captivity
Collectible 19: Stranded Journal (Jennifer)
After releasing Baird from his cell, check to the right in a small alcove.
Chapter 6: Intestinal Fortitude
Collectible 20: Car Gold Magazine
Head left as soon as you start the chapter to find the magazine on the floor.
Collectible 21: COG Tags
These can be a little hard to see. After you find Carmine, but before you reach the ramp, look around on the floor to the left.
Act 3: Gathering Storm
Chapter 2: Origins
Collectible 22: New Hope Journal
After Command tells you to proceed deeper into the facility, check in the small office to the right as you enter the new room. The journal is near a Boltok pistol.
Collectible 23: New Hope Memo
This collectible is in a small room connected to the main hallway. You have to kick down a door in this room to reach the memo.
Collectible 24: New Hope Medical File
Later in the chapter, you will come across a room with a few turrets on the ceiling, and a switch at the back of the room to deactivate them. In the small room behind the switch you can find the New Hope Medical File.
Chapter 3: Rude Awakening
Collectible 25: New Hope Journal
After exiting the facility, do not get on the train. Instead, go right, and go inside the small building. The New Hope Journal is on the floor at the back.
Collectible 26: Captivity Marks
Before boarding the final train, turn around, and go inside the building at the back of the train yard to find the Captivity Marks scratched on a wall.
Chapter 5: Displacement
Collectible 27: Stranded's Journal
After you fight the flame grenadier and destroy the gunboat, check in the middle of the area for a short set of steps. The Stranded's Journal is at the top of them.
Act 4: Hive
Chapter 1: Priorities
Collectible 28: Locust Terminal
The Locust Terminal is in the same room where you have to activate a terminal to search for Maria. Do not activate the first terminal yet. Instead, check the second terminal to get this Collectible.
Chapter 2: Answers
Collectible 29: Locust Prisoner's Journal
Once the Mauler, Theron Guard, and Drones have left or been dealt with, before checking the terminal, look to the left of it near the cavern wall to find the Locust Prisoner's Journal.
Chapter 3: Hornet's Nest
Collectible 30: Locust Jailer Document
Just downstairs from where you enter, turn right, and go down the small corridor. You will find the Locust Jailer Document on the floor.
Collectible 31: Human Finger Necklace
This Collectible can be easy to miss. After you defeat the pair of Grinders that come out of the large doors, you will need to Roadie Run to enter the small room with the Troika before the door closes. If you do not get through the door in time, Roadie Run up the steps and across the room to get in the second door before it shuts. The Human Finger Necklace is behind the Troika.
Chapter 4: No Turning Back
Collectible 32: Locust Calendar
Go up the stairs just after you start the chapter. The Locust Calendar is the round thing with glowing orange lights on it, against the wall.
Collectible 33: Locust Defensive Plans
After pulling the lever to extend the bridge, run across it, and turn left. The Locust Defensive Plans are at the end of the hall.
Chapter 5: The Best-Laid Plans
Collectible 34: Locust Invasion Map
Before getting on the lift, go around the outside of the palace to find the Locust Invasion Map in a little alcove just past the lift.
Collectible 35: Trinity Of Worms
Before heading down the spiral staircase, climb the staircase on the right (where the Grinder was). This Collectible is a pattern on the floor at the end of the hallway, beyond the stairs.
Chapter 6: Royal Inquisition
Collectible 36: Locust Tablets
Near the beginning of the chapter, the Locust Tablets are on the floor between two pillars. They are to the left of the computer room, near the corner.
Act 5: Aftermath
Chapter 2: Desperate Stand
Collectible 37: COG Recon Report
After the Raven clears the Locust off the platform for you, head right, and go down the stairs to the lower platform. The COG Recon Report is here, near some ammo.
Collectible 38: COG Tags - Sergeant Devon Jackson
During the final encounter, look on the floor to the right of the Longshot. The tags are on the very right edge of the platform.
Chapter 3: Free Parking
Collectible 39: Jacinto Sentinel Newspaper
Shortly after the fight in the courtyard, proceed to the next area, where you should have to fight a Grinder in the center. The newspaper is behind the wall to the right of the Grinder.
Collectible 40: COG Tags
The tags are near the end of the level, inside a ruined building on the left-hand side of the street.
Chapter 4: Tenuous Footing
Collectible 41: Stranded's Journal
After the building collapses, check in the corner behind a desk which you can destroy to find the Stranded's Journal.
Enter the arcade room on the "Day One" multiplayer map with a character or the Ghost Cam. One of the fake arcade machines is entitled "Murder Simulator", a jab at attorney Jack Thompson, who often labeled Gears Of War (among other games) a "murder simulator".
At the main menu, select the "Multiplayer" option, and set the match type to "Local". You can play split-screen, and have the person going for the achievement swing a grenade with LT, but do not throw it. Have the other player down him (not kill him), and stand over his body. The grenade will also drop and kill both players. Do this ten times to get the "A Parting Gift" achievement.
At the main menu, select the "Multiplayer" option, and set the match type to "Local". You can set the match to one round with two minutes against one bot (or another controller). Then, just win on every map to get the "Around The World, Again" achievement.
At the main menu, select the "Training Ground" option. At the bottom of the list, choose the "Build Your Own" selection. Set the bots to one, difficulty to Casual, and rounds to one with two minutes. Press Start, and then select the map. Win a game on every map to get the achievement. Note: It is easier to play as the Cog team.
Perform the following eleven unique executions on an enemy to get the "Kick 'Em When They're Down" achievement:
When you have a frag grenade, down an enemy bot or player. Tag them with the frag grenade by pressing B. Immediately afterward, press A to pick them up as a shield. They will explode from the frag grenade that would have killed you. Repeat this ten times to get the "Pound Of Flesh" achievement.
Set up a local multiplayer Warzone match against a second controller. Set it to one round with two minutes. Set the map to Canals. Locate where the two players start. They are at mirrored locations at either end of the map. Quickly kill the second player with your equipped weapon (remembering to note the Torque Bow spawn point is located under a bridge in the center of the map). After the match has ended and you have returned to the Lobby, select the weapon spawning option. Change the Torque Bow to a weapon you need to get a kill with. Start another match on Canals. Leave the rest of the settings the same, though you may change from a COG to a Locust. Go to the Torque Bow spawn point, and pick up the weapon you changed it to. Then, kill your opponent with that weapon. Repeat this by changing the Torque Bow to the desired weapon before each match until you have earned the achievement. Note: You must get kills with the following weapons: Scorcher, Ink Grenade, Gorgon Pistol, COG Pistol, Lancer, Boltok Pistol, BoomShot, Hammerburst, LongShot, Mulcher, Shotgun, Torque Bow, Hammer Of Dawn, Frag Grenade, and Mortar. You do not have to kill anyone with the Smoke Grenade, Troika, or Boomshield. Melee attacks do not count towards a weapon kill. Additionally, you can use this trick to also get the "Kick 'Em When They're Down" achievement.
Accomplish the indicated achievement to get the corresponding number of Gamerscore points: