Curtis Armstrong gave a great performance as Metatron. He was quiet and subdued and still managed to deliver quite a bit of exposition in a way that had me hanging on every word. Bravo, Booger!
The hiding out in identical fast food franchises idea was pretty clever. I know I've mentioned this before but it is cool seeing Amanda Tapping playing such a ruthless villain. I bet she and Mark Sheppard are just having a blast playing off of each other.
Speaking of Crowley, when he first shot his angel-killing gun, my first thought was that he had somehow gotten his hands on the Colt from seasons past. Instead it's yet another cool idea from the mind of Ben Edlund, like Metatron changing the anti-angel glyphs or Cas keeping the tablet in his tummy.
Really cool episode.
The colt doesn't hurt Angels though
That part is unclear. We know Lucifer is one of the five "things" that can't be killed by the Colt. It was never explained if he was referring to himself as a distinct individual, archangels, or angels in general.