Well the "twist" of the story wasn't much of a twist, but that is never the point (well almost never) with this show. The focus of the show (at least how the writers see it) is always character over plot. They don't have the money to tell the stories how they would like to, so its always been lets focus on the characters.
The show has done a couple of episode's where it's them in a town fighting for survival and out of those this was clearly superior, not only in character bit in production.
Bit War certainly could have been handled better. Knowing a show has a finite number of episodes and that they have to seed character arcs, and plot points throughout the episodes, it can make an episode feel disjointed.
But the show is doing things it's never been willing to do before. 1st it split the leads up (and yes it will be more then one episode, how much more I don't know), they have disabled a cast member (for a least a significant part of the season).
It was actually smart to use established characters, in an already crowded episode using established characters allows you to give a damn about if someone will live or die (and yes with those three characters any of them could have died, I actually am surprised they didn't kill some of them).
As for the character beats, they all felt right to me. Though do we always have to be outside near the car fir a heart to heart (yeah I understand its their version of being home, but still).
Liked Castiel being upset,and showing anger at his choice. That was nice. His priorities certainly aren't that of Dean and Sam's. Just heavens and will only side with them as long as he feels it's god's will. I like that, and I hope Dean was actually listening.
Loved the atmosphere of the town. Compare it to Croatoan where the town is invected with demonic virus and everyone out killing everyone else, and yet it was peaceful and calm, no streets in chaos, ect.