A film about two brothers, made by two brothers, Good Time rockets off with a propulsive pace that’s fun while it lasts but understandably can’t be sustained forever.

As the airbags to this continual collision course, however, it’s perhaps telling that the film is bookended by scenes with Nick Nikas (co-director Benny Safdie) attempting to work through his ambiguous disabilities with the help of trained professionals.

At first literally and then for an intensely prolonged period, Nick’s brother Connie (Robert Pattinson) disrupts this progress for an epic 24 hours of well-made and acted cinema that brings him up close and personal with one close call after another.

Film critic cliché or not, Good Time is indeed the kind of viewing experience where it’s best to go in knowing as little as possible — a comment that’s more a credit to the gritty visual and narrative gifts of Safdie and his co-director brother Josh (who wrote the naturalistic as hell screenplay with longtime familial collaborator Ronald Bronstein) than a cop-out.

But by committing to such a dark premise, even with a generous amount of situational humor via tragically humorous lines or actions that seemingly arise naturally from the Nikases’ frantic situation, the film spins its wheels a bit in the third act due to a lack of variety in the siblings’ desperation.

Furthermore, the absence of rationale for the incident that sets Nick and Connie on their make-or-break night beyond a general desire to better one’s situation casts a shadow over what follows, though memorable extended cameos by Jennifer Jason Leigh and Barkhad Abdi (Captain Phillips) offer a welcome balm.

Grade: B. Rated R. Now playing at the Fine Arts Theatre

(Photo: A24)