Cop Car” might merely have been a solid, satisfying excursion into genre-film territory — mostly courtesy of Kevin Bacon, who plays a corrupt rural sheriff in pursuit of two 10-year-old boys who have taken his cruiser on a joy ride — were it not for the fact that its director, Jon Watts, is slated to helm Marvel’s upcoming “Spider-Man” reboot, scheduled for 2017. The movie is entertaining in its own right, in a low-key, slightly campy way, but it’s also potentially revealing in the hints it offers about the forthcoming film.

After Travis (James Freedson-Jackson) and Harrison (Hays Wellford) steal a police car while half-heartedly running away from home, it comes to light that the vehicle belongs to a very bad man, Sheriff Kretzer (Bacon), who has left a bound and beaten man in the trunk of his car, and something worse in a nearby hole in the ground. It’s a simple premise: Kretzer wants his car back — for obvious reasons — and the guy in the trunk (Shea Whigham), once he wakes up and the boys let him out, doesn’t want to see Kretzer again, except to exact revenge. This leaves the children in a tight spot, which Watts, who co-wrote the spare script with Christopher D. Ford (“Robot & Frank”), just keeps drawing tighter, like a noose.

It’s an effective strategy, if at times the danger that the boys are in — including from their mishandling of loaded weapons — is hard to sit through without squirming. Still, “Cop Car” builds up a nice, suspenseful head of steam, mixing dark comedy and true creepiness in such a way that one mood never overwhelms the other.

Bacon, sporting a brushy mustache halfway between a Tom Selleck and a full-on Hulk Hogan, bristles with twisted energy in his performance. But the young actors are particularly good, with Freedson-Jackson nicely evoking the squeaky bravado of elementary school, and Wellford providing a more timid foil. The film is full of quiet little truths, as when the boys run up to touch the cop car and then dash away, as if it were a spaceship, when they first chance upon it.

Go ahead, you can approach this “Cop Car” too, if not entirely without fear.

As Sheriff Kretzer, Kevin Bacon sports a twisted energy, a bad attitude and distinctive facial hair. (Focus World)

R. At AFI Silver Theatre and ArcLight Bethesda. Contains crude language, violence and children in jeopardy. 88 minutes.