In game writing there is a concept we call "theming" which confusingly has nothing to do with the themes of the story, but with the narrative scaffolding of the experience. What does shooting mean in this context? Why is the player doing it? Done poorly, it's a crappy coat of paint on a set of mechanics or systems that flakes or scuffs at the slightest touch. Done well, it becomes a key pillar of the creative vision, something that can drive decision-making throughout the project's development.
But theming can be incredibly hard. While some games are designed with a theme in mind and the mechanics are picked to fit that theme (more common in the indie space), the vast majority of game teams in AAA and mobile are working with the same basic set of repeated mechanics. Each space presents its own challenges. In AAA the verbs are particularly hardened: shoot, talk, run, jump, sneak, take cover. In mobile, the mechanics tend to be very abstract (match-3, merge, link, and of course hidden object), and so difficult to match to concrete verbs.
Thankfully, the "core fantasy" is here to make our jobs easier.
Now, what the heck is that? Let me attempt a definition. When I talk about the core fantasy, what I mean is the main vicarious narrative experience your player has while playing the game, typically but not exclusively inspired by real life activities or common storytelling tropes.
Think about Mass Effect. The core fantasy is "be the military action hero in a sci-fi movie in outer space." Or Red Dead Redemption: "Play a classic Western movie. Or ten of them." Or Stardew Valley: "Abandon big city life to run a farm." Not every core fantasy needs to be quite as on-the-nose as these. The core fantasy of Golf Story is "What if all of life's problems really could be solved by golf?"
A core fantasy is a narrative concept. Not all games will have a core fantasy, even ones with a tight creative vision. (Think of Tetris Effect, with its intense and moving audiovisual experience that builds as you play: there is a clear vision there, but the invitation to the player is to play Tetris like never before, not to become someone or something else.) But pretty much any successful story-driven game you can think of probably has one.
The core fantasy communicates to players what role they're going to play in the game (even if it's not a roleplaying game) and gives them an idea of what actions they'll be taking as part of the experience, and what emotions might accompany it. For many players, you could argue it's the reason they come to the game, why they choose one shooter over another.
And it's immensely useful because it both narrows down what kind of story you're going to tell, but also what features and systems you should prioritize adding the the experience, and how you might theme new features or events as they come onbaord (if you're running a live game.) It becomes a guide to building a more cohesive game experience.
Do the following exercise. Think of a classic detective story. Now, think of what actions the protagonist of that story takes. What are the key elements of the setting? What kind of story does it tell--a gritty one in which everyone comes out looking guilty? A puzzle box full of twists and turns that all come together in the end? A crime scene procedural that celebrates science's role in solving mysteries? Notice how depending on what story you thought of, you come away with a very different set of expectations for your game. A CSI-inspired game should have very different mechanics from one inspired by Raymond Chandler. A core fantasy does more than describe the game's genre, or the player character's job: it tells you what your player expects your story to feel like, what tools the player expects to have in their mechanical toolkit.
I've been playing Assassin's Creed Valhalla recently, and one of my observations in the early hours is that the settlement you slowly build as Eivor works to tie the game's many systems into the central fantasy of being a Viking. I feel motivated to go raiding because I can expand my settlement. Likewise, when I'm out exploring in the world, I'm finding resources for the settlement. The main quest chains (so far) have all centered on the Sons of Ragnar's invasion of England, which is important to me as a player and as a character because I've chosen to settle there. It feels as if the team gave serious thought to the core fantasy of being a Viking, and how both to deliver that experience and motivate players to participate in it. Contrast it with Assassin's Creed Black Flag, a game with terrific ship mechanics and battles that the main quest rarely used; you spent most of your time in that pirate-themed game doing the same ol' Assassin's Creed things you did when you were a landbound assassin in Renaissance-era Italy.
Now, you can sometimes have a secondary fantasy in your game. But this is challenging. Some fantasies go better together than others. Playing a choose-your-own adventure relationship game in Mass Effect fits with the "collect a ragtag band of misfits for your crew and earn their trust" element of the game's core fantasy. Centuries-old conspiracy theories and sneaking assassinations are a more awkward fit with the viking fantasy of Valhalla. The developers solve this poor fit by giving the player the option to be sneaky or to charge in with their crew; in other cases, they find ways to tie assassinations into the player's viking story, by making it a means to gather info and win allies as part of their conquest of England.
In June's Journey, we had the difficult challenge of tying the island-decorating game into a detective story. We bridged the gap using the story: June stumbles into detective work when her own sister is murdered, leaving her in charge of the family estate. The early investigation scenes in the game take place on the estate, and the actual themes of the story are about responsibility, family, and making peace with the past. The estate is a key part of that ever-present personal narrative for June, and its growth represents not only the player's progress in the game, but her progress as a character.
There are many other advantages to having a core fantasy beside what I've already discussed. If you're working on a live game, it helps you focus the theming of new features and events ("how can we enrich, deepen, or expand the core fantasy?" is an essential question when adding new features.) It communicates a clear, easily digestible marketing message. It makes it easier for stakeholders who aren't familiar with the details of your vision to get excited about what you're going for.
But there's one more thing a core fantasy does, and it might be the best of all. Because it sets expectations, it also allows you to subvert them. To play with the tropes your player expects and say new things using a familiar template. And that's something writers love to do.