I didn't know how to feel about Constantine as a TV show since (1) he's a complex yet popular character so expectations would inevitably be high, (2) the Constantine movie was a mixed bag and (3) CW shows did not inspire much confidence. In other words, there's a lot that could go wrong with the show or even if it were good it's hard to expect it to survive for long.
And as is often the case of genre entertainment on major US television networks, the show only lasted a single season and did not go beyond that one. And while the series was not perfect, it hit a lot of the right notes and it was a shame to see it gone so soon.
Synopsis: Constantine is an NBC supernatural drama series created by David Cerone and David S. Goyer. The story is based on the DC Comics character of the same name as originally featured in the Hellblazer comics created by Alan Moore, Steve Bissette and John Totleben.
John Constantine (Matt Ryan) is a sort of detective for cases that involve the occult or threats of a more supernatural nature. But he's not entirely a good guy - he has been more of a con man and opportunist and more recently he's a man trying to make up for past mistakes - mistakes that have cost him his very soul, so to speak. His main companion is Chas (Charles Halford), who makes for a loyal companion. He's also not very good at dying.
Things get interesting when Constantine meets Zed (Angélica Celaya), an artist with some psychic abilities that ends up painting several pieces depicting Constantine. Initially she's a bit of a curiosity and in time she becomes part of his regular misadventures as they deal with a seeming increase in demonic activity in the world.
What I Liked: Matt Ryan made for a pretty good John Constantine, especially in later episodes. Despite the limitations of TV, he managed to depict the sort of jaded, two-timing Constantine I'd expect who's just as likely to use trickery to beat an adversary as much as he'd try magic to accomplish the same goals. And his banter with Chas and later Zed do help carry the show forward.
The writing as a whole certainly showed a lot of potential. While the initial foray into the creature of the week format is standard in TV shows, its later shift to a more long-term narrative was really building up to something bigger that I expect would have been pretty awesome had the show gotten more than its limited 13 episodes.
What Could Have Been Better: While there were some great story pegs with a promise of big things in the future, some of the individual episodes felt a little wonky with some plots that didn't quite seem as truly being Hellblazer worthy, if you get my drift. It takes a while for the show to find its voice and stride but in the end it was too late.
I had very mixed feelings about Zed in the story as she felt like more baggage for John and an odd effort to play to TV expectations of having a clear female character at the forefront things. She's not terrible but she just didn't feel absolutely necessary to the core Constantine narrative. Constantine may be the sort of con man who has a lot of debts and favors to collect on with various figures but that doesn't mean he needs constant companions.
TL;DR: Constantine was a show that was just warming up, really, and I think had a lot better stories to tell in the future. However they never got that far and got bogged down in freak of the week stories to some extent and thus the TV axe came sooner rather than later. So the first and only season gets a decent 3.5 tricks that Constantine orchestrates out of a possible 5.