So throughout the entire show they took care to maintain proper space physics. No fire in space, no explosions in space, no sound in space, that sort of thing. This was typified in the episode "our Mrs. Reynolds" where they use the spare space suit to fire Vera at the net.
Then in the movie they completely throw that out the window and we get sound and explosions and fire in space. The height of which was the space battle between the alliance and reaver ships.
Did this bother anyone else? It definitely rubbed me the wrong direction.
It is the one big flaw, not just from a "it's bad physics" perspective but also from a continuity from the show angle.