The episode title was "Hell's Angels" until just a few days before airing. It was changed after notice of trademark infringement by Hell's Angels Motorcycle Corporation.
This is the first episode that mentions Angel's grace.
When Anna is talking about getting her Grace back, Dean comments "so what, you're just gonna take some divine bong hit and suddenly you're Roma Downey?" This is a reference to the popular 90s TV series Touched by an Angel (1994), in which Roma Downey played the angel Monica, who masqueraded as human in order to gain people's trust to help them, and typically eventually revealed herself as an angel by showing her halo (which appeared as a sudden flood of golden light over her head and shoulders) in order to convince the people she was helping.
When Uriel and Castiel tell the boys that Anna is "far from innocent" and demand they hand her over, Dean tells Uriel to get another girl and to "try JDate." This is a reference to the popular online dating site for Jewish singles.
"Heaven and Hell" is the album title and title song of a Black Sabbath album while Ronnie James Dio was the singer. It was also the touring name of Black Sabbath under Ronnie James Dio, after Ozzy Osbourne came back to front Black Sabbith. The band was a collaboration featuring Black Sabbath founding members Tony Iommi and Geezer Butler along with former Black Sabbath members Ronnie James Dio and Vinny Appice.