Now that this movie is available on DVD ....

Rating: 8/10 (13 September 2016)

My advice is to watch it more than once. I saw it once in a theater and was mostly baffled by it, and came away with the vague impression that the entire movie was an intro to two younger characters and a dash to find Luke Skywalker. But now that it's available on DVD and I can watch it repeatedly, and replay difficult scenes, I can appreciate the more subtle nuances of the plot and I am better prepared for the future films in the series.
I might add that the people responsible for the Star Wars franchise seem absolutely devoted to avoiding any contradictions in the plots of the various different presentations - films and TV programs (even the animated and Lego adventures) - which is a considerable distinction from the people involved in the Star Trek franchise (any explanation of Spock's marriage?). At the same time, Star Wars fans seem perhaps too devoted to the minutiae of even the trailers - I have seen long streams of e-mails devoted to conjuring elaborate interpretations out of two- second glimpses in the Rogue One trailer. If only these people paid that much attention to the Holy Scriptures!