Gun features an action role-playing game environment, including side-missions that add to the story.

They act as gunslingers protecting righteousness or seek reputation as they face resistance fighters, local lawmen, renegade soldiers and vengeful Apaches and Blackfoot.

As the player progresses through the game, they can choose to complete side missions, including poker tournaments, cattle herding, law enforcement, time trials and bounty hunting.

Attacking and killing enemies fills up a Quickdraw gauge which, when activated, slows down time like bullet time, switches the game to a first-person perspective and gives the player unlimited ammunition for a short duration, allowing the player to take on a significant number of enemies.

Stealth plays a part in many missions as well, and players are encouraged to use bows, melee and, on the PSP version, throwing knives, in such situations.

The story, written by Randall Jahnson, features several veteran actors, including Ron Perlman, Lance Henriksen, Kris Kristofferson, Brad Dourif, Tom Skerritt and the lead, played by Thomas Jane.

The game features a number of characters whose names are taken from real Old West figures, including Clay Allison, Jose Chavez y Chavez, Hoodoo Brown, Dave Rudabaugh, John Joshua "J.J" Webb, Luke Short, Major Tom Magruder (who was most likely based on John B. Magruder), Soapy Jennings (who was based on Soapy Smith), and Magruder's hulking personal bodyguard, Dutchie, based on "Dutchy" Schunderberger, a member of the real-life Hoodoo Brown's Dodge City Gang.

After losing ground to Reed's men, Ned tells Cole to find a prostitute named Jenny in Dodge City.

Colton is then brought before Thomas Magruder, Reed and Hoodoo's boss, who had also ordered the Steamboat Massacre and Jenny's murder.

Soapy departs for Dodge while Port takes Cole to the Resistance's Hideout, where he meets their leader, Clay Allison.

Cole later learns from Clay that he and Ned had served under Magruder during the Civil War, and that the former Confederate Major was searching for Quivira, a lost city of gold, and that his ruthless quest had torn the West apart.

Cole convinces Port and the rest of the Resistance to attack Empire, rescue their leader and take out Hoodoo.

After Cole saves Soapy from a lynch mob, the pair escape Dodge and travel to the wreckage of the steamboat.

Many Wounds explains that his father and many other innocent villagers, were murdered by Magruder and his soldiers during their original search for the Cross of Coronado during the Civil War.

Magruder returns to his mine to find the City of Gold, while Cole fights his way down the mountain to save Soapy.

Clay and Cole then use the train to break into Magruder's Mine, which is then attacked by a joint force of Resistance fighters and Apache warriors.

The two then furiously battle inside the Lost City, with Cole eventually overcoming the ruthless tyrant and causing the mountain to begin to collapse.

Cole leaves Magruder with his leg trapped under a rock to be crushed by the crumbing mountain while he escapes the Lost City with the help of Many Wounds.

Then, with Magruder dead and Quivira lost for good, Cole tells Many Wounds that their fathers can finally rest in peace.

[15] GameSpot described it as "initially a 19th-century Grand Theft Auto",[12] while GameSpy addressed it as having "just about everything you could want from a game set in the Wild West".

GameSpy awarded it "Editor's Choice"[22] and "Xbox 360 Action Game of the Year", saying that it "needs a sequel and fast".

On the now-defunct GamerGod.com website, contributor, Beth Dillon, concluded on January 31, 2006, that: Even though the historical period portrayed in Gun was fraught with racism, Activision's decision to publish a racially stereotyped video game represents a serious misstep in social responsibility.

[30]The game's publisher issued this brief statement: Activision does not condone or advocate any of the atrocities that occurred in the American West during the 1800s.