I love Firefly. I love Serenity. I love graphic novels. I did not love Serenity: Those Left Behind. It was a pale imitation of the canon's greatness.

What I didn't like:

The back of the comic said this bridged the gap between the show and the movie, but it didn't. Apparently it is the first in a series that eventually bridges the gap. I don't need to buy and read multiple comics to get to the end of a comic series that leaves me at the beginning of the movie I've already seen (multiple times).

The animation irked me, as the characters' likenesses fell in the uncanny valley.

The cursing in Chinese did not work at all in the written format.

There were multiple plot threads that didn't get any resolution.

Spoiler

The loot getting taken from the crew at the bank, Badger's treachery, Simon and River vs. the Men in Blue Gloves, Mal and Book, Mal and Inara. Basically everything other than Lawrence Dobson getting killed

What I did like:

The Nathan Fillion introduction was great.

The dialogue was spot on, which shouldn't be surprising, considering Joss Whedon wrote it.

Getting to spend time with the crew again, even in this format, was still a worthwhile hour's diversion.