Lead and Gold: Gangs of the Wild West (Steam key).

http://store.steampowered.com/app/42120/
Lead and Gold: Gangs of the Wild West is a third-person shooter that delivers an intense team-based multiplayer experience. Relive the violent era of the Wild West with adrenaline-fueled action and fast-paced gunfights. Engage in gritty battles in beautifully rendered classic Western settings. Players will test their mettle in genre-specific game modes and levels tailor-made for satisfying team play.

Lead and Gold features the unique synergy system, which provides power-ups to encourage co-operation and team tactics. This system accentuates the frantic shooter and objective-oriented gameplay by rewarding players who focus on cooperation and play as a team.

Four playable characters with different strengths and weaknesses, adding depth and variety
A multitude of different game modes and settings, all with a distinct feeling of the Old West, providing increased longevity
Lead and Gold: Gangs of the Wild West uses the synergy system to reward players that play as a team
Game modes and mechanics are designed to be easy to understand