Wow, this is just perfect, exactly what I'd love to see happen at the start of S15 except I don't want Jack to still be dead! I love how easily they dispatch the zombies, how Cas goes up to check on heaven and leaves us with Sam and Dean trying to come to terms with what happened and admitting that they're both done with it all. And this really brought home how much suffering they've been through - "You've burned a father together, and a mother, and a son. You've burned a surrogate father and a best friend." *sobs*