Player fantasy
Also said as Power fantasy, Class fantasy, Role fantasy
Who the game lets you feel you are: a dragon, a master thief, someone who gave up a desk job to run a farm. It is a promise that the numbers, the verbs and the art all have to keep.
It settles design arguments that rules alone cannot. If the fantasy is a dragon, then a villager cannot take twenty hits, however well that balances on a spreadsheet.
Say it
“The fantasy is a heist crew who are always one step ahead. So when an alarm goes off, it should feel like part of the plan. Do not make it a fail screen.”
Where you’ve seen it
Stardew Valley opens with you at a grey corporate desk, opening a letter from your grandfather that leaves you his farm. The fantasy is stated in that first minute, and the rest of the game keeps it.
Not to be confused with story
The story is what happens. The fantasy is who you get to be while it happens, and it can be fully present in a game with no story.