Definitely worth renting, but not necessarily a keeper!
Now I hate to read reviews for this game where the reviewer states that the game play is "repetitive" when this game is most definitely a shooter. In my opinion any game classified as a "shooter" is destined to contain repetitive game play on some level or another. However what makes a shooter interesting and worth playing is the action, the non-stop intensity, and the storyline. As far as action is concerned Neversoft did an excellent job of making sure that the game is filled with enemies for you to eviscerate or in some cases vice versa. But as far as non-stop intensity is concerned, this game certainly contains its fair share of slow points. The storyline is where Gun suffers the most. A rather generic plot with an average climax at best.
Here's where I'll level with you folks, the last paragraph aside I'll say that this game does provide a few good hours of entertainment if nothing else. The horseback riding is well done as well as the gun-fighting while on horseback or on foot. The side missions are usually short and very simplistic, but what really gets me is how Neversoft worked a skill system into a shooter. A very Tony Hawkesque skill system to boot! Personally I feel a classic shooter should never include a skill system. A player's skill in a shooter is measured by his ability to combat his foes, not a stat bar that can be viewed from the start menu. But in any case, Gun is certainly worth renting however, I wouldn't recommend dropping sixty bucks for a new copy if you're heart is set on purchasing your games.
Overall Gun provides a few good hours of entertainment mixed in with mediocre graphics and somewhat challenge gun-fights. However the storyline is rather poor in many aspects and game has it's slow points (like doing side missions for stat points and cash).