Concept for a horror film: You're trapped in a deadly escape room-style situation with jump scares and death traps and such. You have 77 minutes and 34 seconds ("hE:LL" upside-down on a seven-segmented display) to get out.
It kind of also works 'cause that's about the length of a feature presentation.
"Welcome to hE:LL. You're here because someone wants you dead. I am not so heartless. Should the time on this clock expire while you're still in there, however, so shall you."