CKG is a very concise, but well told story. It wastes no time on details that are not directly relevant to the immediate plot. Vampires are overrunning the world; humanity's last weapon is a reincarnated warrior with an attitude problem, but the martial skill to destroy these otherwise immortal monsters. Gunther's lack of faith in humans is a pervasive theme, and he accepts the role of saviour only to ensure his own survival. He is contrasted by Arien, his human power source who has survived to this point relying on people's benevolence and believes they are worth the sacrifice. The art is very stylised, but wonderfully consistent. The gore isprevalent (many vampires have bodies made literally of blood, and Gunther himself frequently loses and replaces bodyparts during battle.) but somehow apt and not that excessive. More of a red backdrop to the proceedings.
Major characters are broadly lumped into noble & heroic, or selfish & manipulative. They're relatively shallow overall, with only Gunther himself being the focus of and character growth.
Everyone has fairly clear goals and motivations and stick to their principles generally.

The ending is somewhat unoriginal (one might say lifted scene for scene if you've seen Terminator 2), but not entirely out of place.
It's a well told, simple story. No major twists, or any deeper message than "greed leads to destruction".