Ask for the shape of the challenge.

The difficulty is logistics — weight, terrain and route planning — with combat as an interruption you are usually allowed to walk around.

Nothing in it is hard to do; almost everything in it is hard to find out that you can do.

Nothing fails quickly. A road laid in the first hour becomes unfixable in the twentieth, and that delay is the only real difficulty in it.

A build with no points where it matters hits walls it can neither talk nor shoot past. Hardcore mode adds logistics, and the Deathclaws north of Goodsprings teach direction before the game does.

Classic mode makes every death permanent, and the calendar decides months in advance who will be strong enough to survive. Maddening turns recruitment into its own strategy layer.

Depth and darkness rather than combat. It is careful never to tell you where to go, which is either the appeal or the wall depending on the player.

Deity is an economy handicap rather than a smarter opponent, so the skill is knowing which of forty systems can be safely ignored this particular game.

Two games at once — a campaign map that decides the war and real-time battles that can still lose it. Army composition answers most questions before the fighting starts.

Poker hands as a scaling problem. The ante climbs faster than a fair deck can, so a run lives or dies on whether the multiplier joker you needed ever appeared in the shop.

A fishing game with an inventory puzzle and a night timer. Panic is the mechanic, and the punishment for giving in to it is deliberately mild.