Call of Duty 3

Here are some acheivements that can get you 100 Xbox Live Gamerscore Points:

Close Quarter Combatant - Complete a mission without firing a round. You can still use melee attacks and hand grenades.

Here are some acheivements that can get you 5 - 15 Xbox Live Gamerscore Points:

Basic Training (5) - Complete the basic training in the beginning of Saint Lo.5.
Purple Heart (5) - For perserverence despite grevious injuries.
Canadien Highlander (10) - Complete 2 missions as a Canadien Soilder.
Polish Tanker (15) - Complete 2 missions as a Polish Soilder
Battle Scavenger (15) - Complete a mission by firing only German weapons. Melee attacks DO NOT count.
Assault Trooper (15) - Complete a mission by firing only assault rifles. Melee attacks DO NOT count.
Supply Officer (15) - Supply ammunition to at least 20 friendly soldiers in a single ranked match. (Multiplayer only)
Rifleman (15) - Complete a mission by firing only bolt action rifles. Melee attacks DO NOT count.

Successfully complete the game to unlock interviews with veterans Gordon Boulton, Sgt. John D. "Bud" Hawk, and Sgt. Stan Markut.

Note: This trick only works when playing an online match. Find a game that is playing at Eder Dam online. Go to where all the sheds are located and the Allies regularly start CTF games. There will also be a jeep respawn and boxes out in front of the sheds. Go down to the edge of the map where there should be a broken bridge and more sheds. Take the motorcycle that is near a fence and the broken bridge. Get onto the motorcycle in the driver's side and drive up to the part of the shed on the left when facing down the hill. After that, drive into that open part of shed. Accelerate while turning into the top left corner. Following this, continue accelerating and turning, but while doing this exit the vehicle. If done correctly, you should have entered a see-through chamber which is not meant to be entered. You can see 360 degrees around and it should be clear. Note: There is also a window frame here, and if you walk up to it until you cannot continue further, you should be pointing the barrel of your gun out and can shoot at enemies walking by. They will not be able to see you through the solid outside. It is also recommended that you take in either a support or anti-armor class so that you can resupply yourself with ammo. You cannot exit the chamber. You must either respawn or kill yourself to exit This also works in many other nooks and corners in the online games, but only in the maps that have motorcycles in them.

If you particularly like a specific weapon from your faction, such as the M1 Garand or Bren, use the following trick to get more ammunition. Find a character on your team that is not an unkillable character (for example, Sgt. Dixon, or Lt. Robiechaud) and melee them. More often than not, the game will not fail the mission. Pick up the ammunition and continue the fight.

At the chapter selection screen, hold Select and press Right(2), Left(2), Square(2) to unlock all levels and bonus content.

To move your friendlies, use ADS and aim at them, then press Fire. Do not worry as you cannot shoot at a friendly. Your friendly should move from his location. This is useful when you are trying to enter an area blocked by a friendly.

When playing in multi-player mode, you can avoid being seen by going into the tall grass. Keep moving back and forth because the enemy can see you because of the red hash marks.

When you meet up with the French rebels you will have a choice to go left to the Flak 88s or go through the house to
the right. Go left to the guns. Kill all the Nazis around the gun and in the ditch leading to the next gun. Then, blow up the 88 and move on to the rest of the guns. After you blow up all the guns you will reach the house that you would have had to take if you went right. When you go in the house you must defeat a Nazi that is standing there waiting for you. Kill all the enemies in the house and fall through the burning floor. You will see you allies there waiting for you.

At the Poisson map, there is a barn or house behind a Nazi Tiger Tank spawn. This part of the map is the part where the Nazis generally respawn. Go in and there should be a ladder. Climb the ladder, then walk over to the window in the front. To your left should be some boxes. Back up. Get prone and crawl up to the corner on the left side of the boxes. Crawl until you cannot move further. Then, stand up. If done correctly you should be apparently on top of the roof. Although you cannot move, you will have a great sniping position. If you prone again you will be back inside the house. You will also have a great view on the little town area and the road to the right that leads up to the house that is next to the other Tiger spawn point.