Season 3 is very reminiscent of the Coen Brothers' movies. So, while it is on the surface a 'mimetic' show (if you like) below the surface is a spiritual allegory and a dramatisation of myth. At the moment I feel the storyline draws heavily on Faust. I feel this season Walter is possessed and protected by evil, symbolised by a plastic eye watching over him, and that Giancarlo Exposito (fine actor) as Gus Fring is Mephistopheles. I think there's a slight tendency in this season (and in some of the Coen's work) to map 'Mexican' onto 'evil' and the border as a the border between earth and hell, through which demons come, which is a bit problematic. I am not saying the makers of the film are racist, I think they would bend over backwards to be the reverse, but I think it is a problematic decision.
I'm not a massive fan of the Faust story because it seems to be a reaction of the Dark Ages to the Enlightenment: your science with its pride and intellectual curiosity will bring you earthly rewards, but damn your soul. Which I think is a pretty nasty message. Event Horizon was an SF film with a similar premise. But, in the long run I don't know whether this story will take Walter down to hell, or whether the Road to Excess will Lead to the Palace of Wisdom (as Blake said).
I think the young drug dealer Jesse Pinkman is the innocent Gretchen, who is lead astray by Faust, and loves him more than he deserves.There's a lot of supporting material on the web placed 'by' different characters in Breaking Bad, and here is an animated panegyric for Team SCIENCE created by Jesse Pinkman. It is packed with subtext of various kinds.
So, Breaking Bad began as a fairly standard black comedy, about a mild mannered guy straying from the straight and narrow, using a science gimmick each week to escape from a set piece problem. Then through season 1 to 2 the moral issues stopped going away, and season 2 ended with him killing hundreds of people and destroying his family and protege. As I say, season 3 seems to have him embedded in evil, vainly trying to escape back to what he was. I am fascinated as to where it goes next.