Revolver is a family of games, currently including:
Revolver: The Wild West Gunfighting Game (aka Revolver 1)
Revolver 2: Last Stand At Malpaso (aka Revolver 2)
The Revolver games are two player wild west themed shootout games that share some mechanics, but are independent game lines. These games are set in the same "Revolver" universe.
Revolver 1 has been expanded with 5 expansions as of 2013:
Revolver 1.1: Ambush On Gunshot Trail
Revolver 1.2: Hunt The Man Down
Revolver 1.3: Vengeance On The Frontier
Revolver 1.4: The Tarnished Star
Revolver 1.5: Death Rides A Horse
Revolver 2 is a separate game in this line, and will be supported separately with expansions. The cards from these two games are not compatible with each other.