it starts with Castiel killing loads and loads of Deans. Which is kinda weird, and kind of a cruel beginning, but skip past that and get to the romance. This looks like a shout-out to Destiel, or at least to their great friendship. Where are all the Sams? Or has Naomi only set it up so Cas has to kill Dean over and over again? It seems like an oversight on her part… or because she thinks it'll be easier for Cas to kill Sam, but he needs to practice for Dean. But, to be fair, it's subtle and it's no more than the subtext Destiel usually gets. However, you'd think it would set the tone for the rest of the episode.
Next we have Cas' appearance.