Sure, you could criticise it for being nothing more than constant gunplay, and it'd be a fair criticism, but I honestly can't find much to fault with Gunslinger, and the shooting is done so well that even after
a solid few hours of play I was still having a blast.
In a
few hours you'll have a passing knowledge
of the layout, within a day or two you'll know the roads pretty well, and within a week or two
of solid playing you'll know them intimately.