Theme vs. mechanics

Designers love to argue about whether theme or mechanics should come first. Theme is what the game is about: trading in the Mediterranean, surviving a zombie outbreak, racing camels. Mechanics are what players actually do: draft cards, place workers, roll and move. Neither answer is wrong, and famous designers sit on both sides.

Starting from theme gives you a compass. If your game is about deep-sea salvage, the theme suggests mechanics: pushing your luck as oxygen runs low, weighing heavy treasure against a slow ascent. When a rules question comes up, you can ask "what would really happen?" and often find the answer.

Starting from mechanics gives you a working engine. You know the core interaction is fun because that is where you began, and you dress it in whatever theme fits best. The risk is a "pasted-on" theme, where the story could be swapped for any other without changing a rule. Players notice, and it makes games harder to teach because nothing behaves the way the story implies.

In practice, strong games converge from both directions. The theme suggests mechanics, the mechanics reshape the theme, and after enough iterations players cannot tell which came first. If a rule fights the story, change one of them until they agree.