You eat popcorn, drink a coke, and watch the movie all at the same time, but there wouldn't be any seats in the theatre, since that's not glamorous.
If the popper was popping corn, and they were selling a candy bar, the movie would need a new release of libc to continue. Each time a kernel popped.
They would announce that the next version of the movie would enable colour blind people to watch in colour, and the deaf to hear it, but you'd have to decide which of 13 vision and audio managers you wanted to run, and no application would work across all of them.
The film would break every 15 minutes and in the most important parts because Alan Cox released a new -ac release.
They would announce new breakthroughs in movie technology colour and sound forgetting thats been around for years, because everyone stole it from PARC and Apple.
Every new movie would require a new kernel release and libc.
The projector would claim to take 32mm in file size, but everyone would think it still wanted 16mm film, since everyone feels compelled to mirror 3 year old out of date documentation as much as possible. Resolution would only be determined by posting to the PKML.
They would claim to support all film genres, and the mailing list would be one long flame war about which is best. And which libc you need to enjoy it best. Assuming the kernel supports it.
Every movie would look pretty, but actually have mishmash holding it together, and contain no plot. Ooops! Sorry, that's from the "What if Hollywood Made Movies" list.
They would promise you an action/adventure flick starring Arnold Schwarzenegger and Sandra Bullock, but it would be 2 years late and end up being a sappy love story with 2 stuffed penguins. With no supporting documentation line.
Their projectors must have 'kill -9' buttons, requiring you to start the movie over and over to have any hope of seeing the entire film. Mostly because XFree-86 keeps hanging.
"2^32 seconds? Whose gonna sit through a movie that long??"