It takes awhile to set things up before the story really gets rolling. Those meeting the crew and entering this world for the first time are probably going to flounder a bit. Those already enamored will wish the story had gotten the television season treatment it needed; but will be delighted and horrified at developments in the movie. There's a richness of concepts ... http://letterboxd.com/mharbour/film/serenity/
it's more of an episode rather than a film. And though it maybe was not the best, (more of plot, not character, driven) but it was the finale the Firefly needed to make the series a true legend, not another 'Universe' for studio to cash out from merchandises and endless non-canon spin offs.