The good old Wild West, 360 style!
Like most people have said, I agree, the graphics are certianly not up to the 360 standard, more along the lines of the normal xbox graphics. However, the number of missions you get to play and the actual gameplay itself more or less makes up for it.
If your the kind of person that goes after achivements, Gun will take you quite a while to get the full 1000. Overall, I think its a great game with lots of different kinds of missions, featuring excellent gameplay and weapons of that time as well as not forgetting the use of travel!