This is an excellent episode that combines everything that makes Supernatural great: action, emotion, uncertainty...and amazing acting.
Jared and Jenson are reliably great, "Michelle", actress Erin Way, has always stood out to me in this episode. She 1000% effectively breaks your heart as you can see all over her face how much pain (mostly emotional, but also physical) she's in. Her performance is perfectly compelling and understated all at once. I would love for the writers to bring her back at some point. And I always love when "Billie", aka Lisa Berry, makes an appearance.
It's one of those episodes that make you think about how thin the line between good and evil really can be.