I think this episode was one the best of the season. I loved Charlie and I hope she makes a reappearance and maybe DOESN"T DIE! That would be a change of pace. Maybe her lesbianism will allow the writers to keep her alive, because the female viewers won't have to see her as a threat. Of course, I get it though. The Winchesters are in a dangerous business, and the only reason why they aren't dead is that they haven't been allowed to die. Anyway, so Charlie was awesome and here are some quotes to exemplify why:
"These things are gonna eat everyone I know. What kind of douchebag stands by for that?"
"So you're saying you guys are monster hunters. So there are other monsters?"
About Dick Roman: "Your password is 'w1nn1ng' with two 1s? Fail."
"So, good luck saving the world. Peace out, bitches."
My favorite scene of all was the Harry Potter pep talk that Sam gives Charlie. I think it's just adorable that Sam has either seen all the movies or read all the books or both. His knowledge is too in depth to just be gleaned from any media sources. I really like to imagine that he's actually read all the books.
So yes, this episode was really funny, but also did a lot to drive the plot forward in terms of the Leviathan arc. My favorite quote of all has to be from ghost Bobby, where he summarizes the Leviathans plans: "This is about knocking us off the top of the food chain. This is about them Levis living here forever, 1 percenter-style, while we march our dopey, fat asses down to the shiny new death camps at every corner."
So to summarize, I LOVED this episode and want to watch it again if I get a chance!