Various bonuses - Enter "735S653J" or "585A926D" as a code under the "Excusive Content" option at the main menu. If you entered the code correctly, a message will appear. This will unlock extra money for equipment in Single Player mode, extra money for character unlocking in Multiplayer mode, silver weapons in Multiplayer mode, and the Superb Ranger weapon that can be used during the first two chapters.

Very Hard mode - Successfully complete the game to unlock the Very Hard difficulty.

Avoid losing momentum - Jumping and switching weapons while in mid-air is a good way to help keep your current speed and momentum. This helps a lot if you find yourself being chased by someone in a multiplayer game and are low or out of ammunition for your current weapon.

Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

Arkansas Fried Rooster (10 points): Blow up 10 chickens with dynamite.
Magnificent Thirteen (30 points): Unlock all classes (ranked only).
High Noon (5 points): Kill 4 enemies between 12:00 p.m. and 12:15 p.m. (local time, ranked play counts).
Well Invested (10 points): Buy 20 second level and 10 third level upgrades (ranked only).
Drive-By (15 points): Kill a total of 5 enemies while horseback (ranked play counts).
Unforgiven (15 points): Kill 10 enemies as an invincible wanted (ranked only).
Welcome to the Frontier (10 points): Finish a full Wild West Legends game (ranked only).
Crime Does Pay (10 points): Win 5 rounds as an Outlaw (ranked only).
Tin Star (10 points): Win 5 rounds as a Lawman (ranked only).
Been There, Done That (15 points): Play a full Wild West Legends game on every level (both match and revenge match count; ranked only).
99 Scalps (25 points): Deliver 99 headshots (ranked play counts).
Jack of All Trades (30 points): Play a full game with each class (ranked only).
Goldrush! (50 points): Collect a total of $1 000 000 (ranked play counts) to unlock golden weapons in multiplayer.
Crowbait (40 points): Finish the game on at least easy difficulty.
Between Hay and Grass (40 points): Finish the game on at least medium difficulty.
Curly Wolf (40 points): Finish the game on hard difficulty.
Act I (30 points): Complete Act I.
Act II (30 points): Complete Act II.
Act III (30 points): Complete Act III.
Act IV (30 points): Complete Act IV.
Ray's Story (30 points): Finish every chapter playing as Ray.
Thomas' Story (30 points): Finish every chapter playing as Thomas.
D-Day (15 points): On chapter I, destroy all rafts before they land.
Mayhem (15 points): On chapter III, kill 20 armed enemies while riding the stagecoach.
Quite a Ride (15 points): On chapter IX, on the lift, destroy everything that is thrown at you.
Man of the Hood (15 points): On chapter XII, playing as Thomas, use only bow throughout the whole level.
Gotta Catch'em All (40 points): Collect all secrets.
Boy Scout (5 points): Finish one side quest.
Shield of Hope (20 points): Finish all side quests.
Quick Hands (10 points): Kill 7 people during one concentration mode.
Frag Steal (10 points): Kill all enemies in a single Cooperative Concentration Mode.
Untouchable (20 points): Finish any chapter, except for VI and VIII, without getting severely wounded.
Fireworks (10 points): Shoot 2 enemy dynamite sticks in mid air.
None Shall Hide (5 points): Shoot an enemy through a wall.
Mad Carpenter (5 points): Kill 5 enemies with a chair.
Pistol Expert (25 points): Kill 250 People using pistols (ranked play counts).
Rifle Expert (25 points): Kill 250 People using rifles (ranked play counts).
Shotgun Expert (25 points): Kill 250 People using shotguns (ranked play counts).
Forgiveth Me, Lord (50 points): Kill 2000 enemies (ranked play counts).
Rowing-Race Cheater (10 points): On chapter XI, kill all the Indians during canoe chase.
Sharpshooter Distraction (15 points): On chapter IV, playing as Ray, kill sharpshooters without Thomas' help.
Sharpshooter Destruction (15 points): On chapter IV, playing as Thomas, kill sharpshooters in 10 seconds.
Catcher in the Rye (15 points): On chapter II, in the field, kill enemy soldiers using knives without being detected.
Yankee Cow (15 points): On chapter II, don't kill the cow.
Vindicator (15 points): Kill a total of 30 enemies with movable gatling.
On the Right Track (30 points): Collect a total of $200 000 (ranked play counts) to unlock silver weapons in multiplayer.
Old West Legend (40 points): Finish the game on very hard difficulty.