Two men awaken chained to opposite walls of a grimy bathroom. A bloody body lays sprawled on the floor between them. Spoilers follow.

The men are a doctor, played by Cary Elwes, and a private investigator played by co-writer Leigh Whannell. As performers, they illustrate the difference between convincing and engaging. Elwes doesn’t convince as a surgeon, but his innate charisma makes him engaging. Opposite him, Whannell convinces as a low-rent peeper, but lacks charisma.

Also involved is Danny Glover as a detective. Cast to type, he both convinces and engages. But relying on Glover’s established “old cop” stereotype backfires. When the plot reveals him as lacking both detection and basic police skills, it feels dissonant instead of surprising.

These casting missteps mar an otherwise deft marriage of Cube’s single room deathtrap with Seven’s grungy atmosphere and punishing serial killer. The result eschews either film’s grislier visuals in favor of relentless plot twists.

Revisiting the film, I was curious how it would play knowing the twists. While this viewing lacked the first watch’s shock, it lent an appreciation of how well the film fits together. Like a puzzle.