As we know, "Firefly" was cancelled after 11 episodes, performed extremely well on DVD, and so was revived in the form of the "Serenity" movie, which finished off the plot lines for the rest of the season in a severely abbreviated form. However, the movie suffers badly for this, as a whole lot of gaps necessarily exist and, perhaps most crucially, the film makes almost no sense to people who haven't seen the series.
For the past year or more, I have been watching my way through a friend's DVDs of "Stargate SG-1", which ran for 10 years, accumulating some 200+ episodes. Having finally reached the end of the 10th season, I find that this, too, was cancelled without being able to resolve the hanging plot threads. Still, not to worry, because they, too, had a TV movie, "Ark of Truth", which is designed to resolve things. And, fortunately, I happened to have recorded this on Sky when it was on in March.
I watched it last night, and it suffers from exactly the same problems as "Serenity". Firstly, it will make little or no sense to those who haven't seen the show, but that's a forgivable feature. However, it also compresses what should have been a story told over 20 hours of TV into around 2 hours of movie. And so, we have characters changing sides at the drop of a hat (the change was hinted at in the series, but really needed longer to play out), we have people making massively stupid mistakes (where, again, they could have arrived at that as a measure of last resort over the course of a year, but to just jump straight to it was jarring). And I'm pretty sure the climax isn't how they would have done things had they had a full season to work with.
On the other hand, it's an awful lot better than all but one of the "Babylon 5" TV movies, not that that's saying much. It's probably on a par with "Battlestar Galactica: Razor".
Anyway, next up is "Stargate: Continuum", which is their next TV movie. And I'm sure that at some point I'll be compelled to watch "Stargate: Atlantis", but I'm hoping to put that off until next year. I still have quite a lot to do this year, and only 92 days (after today) in which to do it.