After months of anticipation, I have slightly mixed feelings. I think it's adjusting my expectations of the movie with the actual product.
Remember that I am a HARD critic. My standards are set HIGH. I have seen 5 movies this year (more than any year for over 2 decadeS). This is the best movie I've seen this year. In fact, on the SciFi scale... I'd rank this just below the original StarWars... and equal with Wrath of Khan, scoring it the 2nd place in SciFi standing.
But it wasn't the movie I expected. Though I don't know what movie I expected.
Whedon returned to his original vision of Firefly... with a harder, less happy Mal. Whedon also added backstory that made the movie accessible to those who never saw the TV show, but that slightly threw me. The movie is about Mal as captain, and River as fugitive. It places all the other crew members in the background. They are almost cyphers of themselves.
And, though everything said that yes they were in the movie (and they were) Sheppard Book and Inara were not travelling on Serenity when it began. Book never returned to Serenity. So there was yet another mental adjustment. It took time to adjust to the new reality.
Still the story hung together well. And the fight scenes were fabulously choreographed. We learned something important about this universe. And I was again reminded that Whedon used architecture to set the "feel" of each planet more effectively than most directors.
There were a couple really sad moments, and moments of heroism. The movie ended in a way that more satisfactorily wrapped up the story. It is finished and I can save it as a distinct universe now. (like a star trek universe, or a stargate universe) that until today felt incomplete.