Unlock Xbox Live Gamerscore points, by completing the following Achievements.

Achievement	How to unlock
Antietam - Deadeye ( 15 points )	Complete the Antietam mission with an accuracy above 95%.
Antietam - Sharpshooter ( 10 points )	Complete the Antietam mission with an accuracy above 75%.
Antietam - Soldier ( 5 points )	Complete the Antietam mission.
Bookworm ( 40 points )	Find all secret documents in the game.
Bull Run - Deadeye ( 15 points )	Complete the Bull Run mission with an accuracy above 95%.
Bull Run - Sharpshooter ( 10 points )	Complete the Bull Run mission with an accuracy above 75%.
Bull Run - Soldier ( 5 points )	Complete the Bull Run mission.
Captain ( 75 points )	Kill 250 of your enemies.
Chancellorsville - Deadeye ( 15 points )	Complete the Chancellorsville mission with an accuracy above 95%.
Chancellorsville - Sharpshooter ( 10 points )	Complete the Chancellorsville mission with an accuracy above 75%.
Chancellorsville - Soldier ( 5 points )	Complete the Chancellorsville mission.
Chattanooga - Deadeye ( 15 points )	Complete the Fredericksburg mission with an accuracy above 95%.
Chattanooga - Sharpshooter ( 10 points )	Complete the Chattanooga mission with an accuracy above 75%.
Chattanooga - Soldier ( 5 points )	Complete the Chattanooga mission.
Chickamauga - Deadeye ( 15 points )	Complete the Chickamauga mission with an accuracy above 95%.
Chickamauga - Sharpshooter ( 10 points )	Complete the Chickamauga mission with an accuracy above 75%.
Chickamauga - Soldier ( 5 points )	Complete the Chickamauga mission.
Cold Harbor - Deadeye ( 15 points )	Complete the Cold Harbor mission with an accuracy above 95%.
Cold Harbor - Sharpshooter ( 10 points )	Complete the Cold Harbor mission with an accuracy above 75%.
Cold Harbor - Soldier ( 5 points )	Complete the Cold Harbor mission.
Colonel ( 100 points )	Kill 500 of your enemies.
Fort Fisher - Deadeye ( 15 points )	Complete the Fort Fisher mission with an accuracy above 95%.
Fort Fisher - Sharpshooter ( 10 points )	Complete the Fort Fisher mission with an accuracy above 75%.
Fort Fisher - Soldier ( 5 points )	Complete the Fort Fisher mission.
Fredericksburg - Deadeye ( 15 points )	Complete the Fredericksburg mission with an accuracy above 95%.
Fredericksburg - Sharpshooter ( 10 points )	Complete the Fredericksburg mission with an accuracy above 75%.
Fredericksburg - Soldier ( 5 points )	Complete the Fredericksburg mission.
General ( 125 points )	Kill 750 of your enemies.
Gettysburg - Deadeye ( 15 points )	Complete the Fredericksburg mission with an accuracy above 95%.
Gettysburg - Sharpshooter ( 10 points )	Complete the Gettysburg mission with an accuracy above 75%.
Gettysburg - Soldier ( 5 points )	Complete the Gettysburg mission.
Journalist ( 40 points )	Find all secret photographs in the game.
Knife Master ( 50 points )	Kill 75 of your enemies with your knife.
Lieutenant ( 50 points )	Kill 100 of your enemies.
Melee Hero ( 30 points )	Kill 50 of your enemies in close combat.
Petersburg - Deadeye ( 15 points )	Complete the Petersburg mission with an accuracy above 95%.
Petersburg - Sharpshooter ( 10 points )	Complete the Petersburg mission with an accuracy above 75%.
Petersburg - Soldier ( 5 points )	Complete the Petersburg mission.
Pistoleer ( 50 points )	Kill 100 of your enemies with your pistol.
Private ( 5 points )	Kill 20 of your enemies.
Selma - Deadeye ( 15 points )	Complete the Selma mission with an accuracy above 95%.
Selma - Sharpshooter ( 10 points )	Complete the Selma mission with an accuracy above 75%.
Selma - Soldier ( 5 points )	Complete the Selma mission.
Sergeant ( 15 points )	Kill 50 of your enemies.
Shiloh - Deadeye ( 15 points )	Complete the Shiloh mission with an accuracy above 95%.
Shiloh - Sharpshooter ( 10 points )	Complete the Shiloh mission with an accuracy above 75%.
Shiloh - Soldier ( 5 points )	Complete the Shiloh mission.
War Hero ( 30 points )	Complete the game on the Hard difficulty setting.
War Survivor ( 10 points )	Complete the game on the Easy (or higher) difficulty setting.
War Veteran ( 20 points )	Complete the game on the Normal (or higher) difficulty setting.