A solid nine. The game is incredible, but there is no limit to perfection, plus, excessive realism and detail, over time, begins to tire, and not delight, as in the first couple.
However, the overall impression is excellent, really. The setting, again, the details, the way the game basically positions itself, this whole gangster story of the wild west. I recommend you check it out, because this particular game, without going into details, is a work of art. This is how AAA projects should be and nothing else)
9.0