The movie should have been a mini-series at the very least. For what it was...it was very good. However, Deadwood The Series was so much more than "very good"....given the limited length offered to the movie (less than 2 hours) much of the amazing character development which made the show so powerful in the first place was rushed and truly deserved to be given more time to properly tie things up adequately.
It is certainly better than leaving things open ended as they did when the show was cancelled after season 3...however it really serves as a reminder to how much more this show could have accomplished in its initial run and how poor of a decision it was to cancel it in the first place.
Fans of the show will enjoy a return to the characters they held dear....but ultimately will be reminded of what could have and should have been.