As only a casual fan of the original series I may not be able to compare and contrast this movie as well as some others but the producers of this tv film seem to have covered all their bases.
First of all the story was very well done. By basing the movie on one of the original tv shows the viewers were given a sense of continuity that some movies that are based on previous tv shows don't have. Also, the story itself, while not all that original, was well written and suspenseful. Out of the 5 GUNSMOKE movies that were made I felt that this one was the best.
Secondly, this movie did a fine job of bringing back the original cast members. Amanda Blake as "Kitty" and Buck Taylor as "Newly O'brien" helped to give this movie an authentic feel. Having said that it would have been nice if Dennis Weaver as "Chester" and or Ken Curtis as "Festus", both served as deputy under Marshall Dillon, had made an appearance in the movie.
Lastly, while the movie overall was a good one it seemed to me that James Arness portrayed Matt Dillon less like the character in the original series and more like the mountain man character of "Zeb Macahon" in his other western series HOW THE WEST WAS WON. Still this movie is a good view and those who like James Arness or GUNSMOKE will appreciate it.