I have watched the extremely spoilery SPACE promo for the ep, and feel the same way about it I felt about the Canada geese that were the scourge of the New Jersey town where I used to live: bemused, mortified and weirdly gratified that something Canadian can be so disrespectful of the normal proprieties, and so notorious beyond the borders of its native country. One admonishing finger-wag for you, SPACE channel.
The major meepiness is Dean related. He is pleading with the angels, with Heaven, with God, not to make him betray his deepest beliefs, to let him hold onto the hope that he was recued because there was something good and worthwhile in him, not because he had become so corrupted that he was now suitable to do the kind of evil that a righteous being could not. The resignation and hopelessness in his shoulders as he walks through those doors is heartbreaking. The resemblance to demonic!Dean of "Dream a Little Dream", all smooth faced, smiling evil, as he says "Let's get started" is chilling. And the revelation that Dean's breakdown in Hell, after thirty years of torture, was the required first step to the Apocalypse, to make Dean the Judas for the entire human race--well that's just mean.
And as for Sammy--meep meep meep!