Your finished film must run 119 minutes on the dot. The story itself is about runtime, so hitting that exact number is the punchline.

Every single frame must have a clock visible. It can be subtle (a wristwatch, a wall clock, a phone screen) or bold (a massive countdown). But it must always be there. The audience should subconsciously track the ticking runtime.

Marty is the key human element. He's obsessed with time, but missing his watch. He constantly checks his bare wrist, sees the tanline, gets frustrated. Other characters tease him: "Hair past a freckle?" He's always right. Nobody believes him until the end.

At 88:00 remaining, the clocks visibly slow — characters panic, then dismiss it. In Act 3 when the Time Traveler reveals Marty's stolen watch, the clocks speed up. Both anomalies cancel each other out, causing the world clocks to hit 0:00 at 117 real minutes — even though Marty's watch is correct.

At the midpoint, Marty runs off to pee. The other characters stand around awkwardly. For 119 seconds: loud offscreen peeing sounds, awkward silence, cheesy muzak faintly in the background. Marty returns refreshed. The movie continues as if nothing happened.

At the climax, the world clocks hit 0:00 at 117 minutes. Everyone closes their eyes as if the movie is over. But Marty's watch still shows 2 minutes. He tries to convince them. It is awkward, painful, and funny. Then his watch ticks to 0:00.