Gun would have been a really great game if the graphics were truly next-gen. Every part of the game is good except for the graphics.
As the short titles implies, theres gonna be lots of shooting, but its more fun than just aiming and clicking a button. First off, there are different weapons for different things, use your rifles in medium ranged combat, your pistols as a well-rounded weapon, or a shotgun as your close-range weapon. Second, Quickdraw mode, this allows you to slow down time, and quickly switch between targets to blast. Third, there are TONS of guns, there are rifles, pistols, shotguns, bow and arrows, long range rifles, melee weapons, and thrown weapons, and for each of those categories there are about 3 different choices, you do the math, there's a ton of firepower.
The missions are varied, ranging from fighting alone, to fighting with some allies, to horseback missions, to boss-battles. There are also side-missions, while, not amazingly engaging can hold your interest for a little bit after you beat the story anyway.
This is the worst aspect of the game. The visuals look like a PS2 game, not an Xbox 360 game, the textures are low res, the enviornment looks terrible, and the animations are bad. But, in HD the models for characters are pretty good, so thats why the score isn't very bad.
The sound is great. All of the voice-overs are great, some movie stars even lend their talents, and the music really makes you feel like you're in the old west.
The story shouldn't last you a whole lot of time, but there are tons of side-missions to keep your interest.
This was a great attempt at a different kind of game by Neversoft, but next time it has to take full advantage of all the systems' graphical power.