Second Idea

Group of people in a car/ couple together. Body or corpse in the middle of the road. Car stops and people get out. The corpse gets up and kills both of them.
Cliff hanger style, in forest point of view shot of killer. Car shots point of view etc.

Killers presence is felt camera shows killer. Dark clothes.
People killed off 1 by 1, with titles between.
Car steaming up, killers hand on window
Playing towards horror style, not supernatural but more human.
Not a lot of blood needed otherwise it would seem more like a horror than a thriller.
MUSIC: Will be more atmospheric and leads to conclusion, rather than music trying to get a scare out of the viewer. Music must be tense, and fairly straight unlike horror which is jumpy and creepy.