Fiction, Games, Writing

Harnessing the Completion Principle to enthral and annoy your readers

This has happened to me and I’m sure it’s happened to you. Let’s say you’ve been to see a movie and now you’re walking home. The movie was okay, maybe even great! But there was some missing piece which is starting to bug you. ‘Well, how did the McGuffin work?’ or, ‘But why did the villain hate the hero’s mother?’ 

The movie is starting to bug you. You can’t stop thinking about that missing plot point. You discuss it with your friends until they stop returning your calls. You scour the internet to see if anyone else has noticed and find posts of people discussing nothing else. Some have been back to the cinema three times trying to gather information. It only gets worse when the DVD comes out. Now there’s frame by frame analysis. Images are blown up 100x to check what the document on the table behind the hero says. The book the sidekick is reading is clearly the key to the puzzle. 

Is Deckard a human… or a replicant?

This isn’t just nitpicking over a bad movie. We can tell the difference between a bad movie (The Room, I’m looking at you) and one of an otherwise of a high standard with a small inconsistency which rankles. Instead of brushing it off as bad storytelling, people would rather see it as a purposeful mystery left for us to solve. 

While I’m a bit of a sucker for these sorts of ‘theories’, I’ll admit it’s more likely that most of these are genuine mistakes or sloppy writing. Sorry! 

But that isn’t always the case. Pixar is renowned for the Easter Eggs it leaves in its movies for the keen-eyed to discover. They’re creating a deeper level of to satisfy the people who’ll look for one whether the movie wants them to or not.

Then, there’s the Pixar Theory. First created by Jon Negroni, this theory suggests that all Pixar movies share the same universe and there’s one overarching story to tie them all together. It’s pretty incredible if you’re a Pixar fan and the Super Carlin Brothers do a great video about it here. Did Pixar plan this from the beginning, or is this just retconning? Clever retconning, but still, not intentional from the beginning.

Intentionally or unintentionally, what Pixar’s done is give us enough to make us think there’s something deeper going on. A mystery to be solved. Humans are natural puzzle solvers. We look for answers in things that are apparently chaotic or even meaningless. What’s at play here? The Completion Principle.


The completion principle is the reason why you can’t just eat one slice of cake. Why you can’t put a book down mid-chapter or stop before completing a level in a game. It’s the jigsaw set with that one missing piece.

The brain is programmed to know when it’s completed a task. The task is filed away as finished and that’s that. But leave it hanging, uncompleted, and the unconscious mind reserves a little bit of space to deal with it. So we’re always thinking about it.

The Pixar fan community has going crazy over something that may not be true. People willing to return Pixar for every new movie. It’s a level of engagement all authors should be inspiring too. Just look at the Harry Potter or Lord of the Rings fanbase. These creations have left enough hints at greater mysteries for us to always be talking about it, with no resolution in sight.

But there’s an even better example for us to look at. A games creator who, in my opinion, has exploited the Completion Principle to devastating effect.


Five Nights at Freddy’s is an indie game created by Scott Cawthon. Here’s the briefest summary I can manage. You have to survive five nights as a security guard in a restaurant called Freddy Fazbear’s Pizza. Simple? Well, no, because the three Chuck E. Cheese type animatics Freddy, Chica and Bonnie are coming for you and if they get you, you’ll be stuffed into an empty animatronic suit.

Um, now, that wouldn’t be so bad if the suits themselves weren’t filled with crossbeams, wires, and animatronic devices, especially around the facial area. So, you could imagine how having your head forcefully pressed inside one of those could cause a bit of discomfort…and death.

Phone Guy, Five Nights at Freddy’s

Bonnie_blargWhile it was a groundbreaking game in terms of the genre and mechanics, what players went crazy over was the lore. The hidden story in the game which is only hinted at. Who’s the Phone Guy who’s left you these tapes on how to survive? Why are these animatronics sentient and homicidal? Who’s Golden Freddy? What was the infamous Bite of ‘87? There was a dozen hanging threads that you’d puzzling over even as you fought to survive. Even I played it to explore this mystery and I despise horror games. I hate animatronics too, come to think of it. 

Seriously, I’m not kidding. It’s terrifying.

Over the next four games, Scott Cawthon developed and expanding the lore. The internet went insane over this franchise. Reddit post after Reddit post and dozens of YouTubers puzzled the FNAF mysteries. MatPat’s Game Theory channel delved into the game’s source code, trawled Scott Cawthon’s website, researching real-world salaries, cross-referenced minutiae details from the book and even checking the US Patent Register to check the creator’s trademarks.

What the FNAF creator Scott Cawthon abused ad nauseam to his financial benefit (and our agony) is the completion principle. It works. I’ll never be completely satisfied with any theory created to explain FNAF and until I am, I’ll keep playing the games, watching the Youtube vids and even reading the torturous tie-in book, The Silver Eyes. I’ll even end up seeing the movie and, again, I HATE horror. 

So let’s use this. We can create this buzz in our writing. We can create stories with mysteries to be solved and think carefully if you actually want to reveal all at the end. Think of it like this – when the sequels to old beloved movies clear up long-held mysteries, explaining them away in the new movie, are audiences always grateful? Usually, no.

Even if your story isn’t a murder mystery, don’t feel you have to give out every scrap of information. Sometimes, a well-placed, unanswered mystery can live with your readers longer than a story which ties itself up in a neat little bow. 

What are some of your favourite mysteries? Do you prefer to know everything by the end or would you rather have a puzzle to solve? And, more importantly, at the end of the movie, is Dom Cobb awake or asleep? I HAVE to know.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s