I just played through GUN on the 360 and really enjoyed it, and realized that I've enjoyed many previous entries in the wild west genre, from Gun.Smoke in the eighties (the arcade version on Capcom Classics Collection is damn near impossible) to Sunset Riders in the nineties - though GUN is the first wild-west themed game that I've played with a free-roaming world to immerse yourself in.
The 360 version did get flack for being a previous generation title and getting a "slapdash" presentation to the next generation.
But I thought the graphics were impressive enough, and I really appreciated the free-roam world. It felt alive, and the ambient sounds really drew me in. The world was small enough to leave each area feeling unique and distinct.
GUN also had an all-star voice-over cast, including; Thomas Jane, Lance Henriksen, Kris Kristofferson, Brad Douriff, Tom Skerritt, and Ron Perlman.
I do wish that GUN had an epilogue, and it's a shame that there aren't any behind-the-scenes video's featuring GUN's star-studded voice actors!
I was going to play through GUN on the hardest difficulty to get all the achievement points, but after I beat the game on normal difficulty I realized that it didn't also unlock the achievement for easy difficulty. So I'd have to play through the game another 3 times? I think I'll just leave that one alone.
I've never played Red Dead Revolver which is another 3rd person perspective western which was released before GUN, and only available on previous generation consoles. It's never been said that Red Dead Revolver was free-roaming - is it more level based?
Call Of Juarez is a FPS released only on next-gen. I played through the demo and enjoyed it enough that I'd like to pick it up someday.
Funny thing is, now both Red Dead Revolver and Call Of Juarez have sequels in the works, though Activision has never officially announced a sequel to GUN. I'm certainly all for a sequel!