Superb episode. Gorgeous sets, good characterisation, top class fighting on screen and off and exceptionally well cast actors- especially the 'Old Man'- not easy to give a convincing performance, especially in the current Twilight climate, but he really pulled it off.
Supernatural walks a delicate line between being able to take the mick out of itself and, conversely, dealing with relatively ridiculous subjects in a serious fashion. This episode exemplifies just how adept they are doing this.
Top marks and a bucketful of Thanks for making such great television.