It would have been better if Constantine stayed as a Movie.
In the game you go to Hell and then come back and so on. The games gameplay is ok, you can use weapons like "The Holy Shotgun",Holy water bombs that make an half-breed make his flesh fall off/Human disguise, etc etc etc. The game isn't really that scary, actually probably its not scary at all. Though there are some moments when you jump/get scared.
You can even get spells as you progress through the game. You can use spells to inflict alot of damage at your opponents. Even Life Upgrades, and some other stuff. The puzzles in the game aren't so hard except for one or two, now those one or two you have to find out yourself :P
Theres not really much to do after you finish the game. No extra modes to play or nothing. You CAN play the game over again but then that feeling leaves. Probably no one would play it over again.
Again, there's not much to say about the game because, if you've seen the Movie of constantine. It's exactly like that. Constantine isn't worth a buy but it is worth a rent.