Everything wrong with this movie:
-It takes itself too seriously. The introspective narrative voice, the coming of age drama, the constant references to religion are shallow.
These things are not enough to make a "The Road" with a vampiric background
-The plot and the world in which the film is set are full of inconsistencies. At the beginning, the narrator tells us that the situation is desperate and those who have decided to stay together in cities and villages have not survived. A little later they enter a fairly populated city where everyone gets along well and there are also enough resources for everyone...
The protagonist tells us that, however, he doesn't want to stay because his destiny is the street and vampire hunting... later on in the film they load up their car with all kinds of people (a nun, pregnant women, a man that could have been bitten by a vampire, who could slow them down and hamper them in their hunt for vampires) to go towards New Heaven which is supposed to symbolize a return in the civilized world...
-Vampires in this movie are retarded zombies. [spoiler]At one point a character is left alone at night without weapons in the midst of a herd of 6-7 vampires, he comes out unharmed (we don't know how since the director doesn't show us anything) [/spoiler]. Also the scene of the vampire trap with a bloody teddy bear is hilarious.
-The main villains of this film are a clichè group of religious fanatics that have no purpose at all except create chaos, rape nuns and kill the protagonist of the film.
-The final fight is ridiculous, an highlight of the film solved in 2 minutes.

In summary this is a zombie movie without what that makes zombie movies great (the desperate fight for resources and survival, the collapse of trust between people, the selfishness of humankind in desperate situations, the fear that anyone could have been bitten and turn to a zombie/vampire at any moment, the presence of an ubiquitous fearful and implacable enemy etc..)