A good episode overall, and it definitely sets the precedent for the rest of the series.
Starts off with the famous John Wayne introduction, where he says that he thinks Gunsmoke is a great show, very gritty and very adult. (For those of you who have only seen the color episodes, I will state that the B&Ws are nowhere near as warm and fuzzy, and end unhappily as often as not.) The Boot Hill opening fits in well, serving as a second introduction with a little more insight into the show.
The plot is good. A gunman named Dan Grat comes to town and almost immediately embarks on a killing spree. Unfortunately, all are fair fights. Matt realizes he must stop Grat, and manages to goad him into a gunfight, but Grat is faster (!!!) While Matt is recovering, Kitty tells him more about Grat, and it turns out that even though he is the fastest gun Dodge has ever seen, he does not take the time to aim and must be at close range. Once Matt is well, he persuades Grat to fight him again, this time at a greater distance, and is successful in defeating him.
The characters are true to life from the beginning. Chester is immediately shown to be somewhat lazy and a bit slow to comprehend. Matt, of course, is the stubborn, joking, hard working law man from his very first scene. Kitty obviously cares very much for Matt, even this early in the show. Doc is cantankerous and a bit ornery (he mellowed considerably as time went on).
The acting is pretty good. It left a little to be desired in some of the early episodes, as the actors were still getting to know the characters, but I didn't see any major problems here. Everyone seems to know what to do with their hands, and there weren't any "dramatic silences."
Sets and props are nice, costumes are great (I love the "normal" dress Kitty is wearing in Doc's office, very simple and pretty), make up is well done, and all the little details that make the great shows great are there.
As I said, a very good episode overall, and a wonderful launch to the series!