World and lore
Cast a cutscene from whoever is in the party right now
The scene was written for the healer and the thief, but the healer stayed in town and the thief is dead. Here is how to give every part to a present character, never the same one twice, and to report plainly which parts nobody can play.
Find the borders where a mild region meets a deadly one with no warning
The player steps over a stream and the wolves that were harmless a moment ago are replaced by creatures that kill in two hits. Here is a check that looks at every walkable border on the map, ignores places the player cannot reach, and says how much buffer the story needs.
Tell the player where something lies in words, like north-east and far
A villager who says the cave is north-east of here has to be right, and not off by a quarter turn because up on the screen is down in the numbers. Here is a way to turn two positions into one of eight directions and a distance word, with the borders in the right places.
Run a countdown to disaster that moves with the player's choices
The siege begins in twenty days, and the player should feel every day spent: a rest costs one, a long errand two, a chat nothing. Here is a clock that counts actions, warns at the right moments only once, survives big jumps, and waits for a cutscene to end before it strikes.
Check that every door puts you where you expect and leads back
Walk through the cellar door and arrive inside a wall, or step out of the inn and land at a different door of the village, or ping-pong between two rooms forever. Here is a check of all doors at once that finds these before the player does.
Generate a dungeon where every key lies before its lock
Random dungeons sound great until the generator puts the blue key behind the blue door. Here is a way to build the rooms and hand out locks and keys in an order that always leaves a way through, no matter what the dice say, with a check you can run afterwards.
Bring a cleared enemy camp back only after the player has been gone a while
A camp that refills as soon as the player turns around feels cheap, and one that never returns leaves the road empty. Here is the rule that counts the days away, not the days since the fight, so camping next to the ruins does not bring the bandits back.
Protect only the characters a running quest still needs
A stray arrow kills the one person who holds the key to the story, and the game cannot go on. But making everyone unkillable robs the world of danger. Here is a rule that knocks someone out instead, only while a quest needs them, and gets them back on their feet.
Let a good deed for one faction anger its enemies, but only once
Helping the guild should please its friends and annoy its rivals, but if friends of friends react too, one deed shakes the whole world. Here is a ripple rule that stays one step deep, keeps small deeds from rounding away, and refuses contradictory friendships.
Let a failed harvest raise prices in the towns around it, less with distance
One town loses its grain and the price of bread rises there, but the town two roads over stays exactly the same, which feels dead. Here is how to let the shock spread along the roads and fade, and what to do when two troubled towns lie near the same market.
Let fast travel be stopped by an ambush on the road
If a jump across the map just moves the player to the target, the world stands still while days pass, and ambushes, storms and festivals are skipped. Here is how to play the days of the trip through and stop the traveller exactly where the world got in the way.
Tell the player how long to wait for the next ferry or caravan
A ferry that leaves every two hours from morning to evening sounds simple until the player arrives one minute late, or after the last boat, or just past midnight. Here is how to answer correctly in each case, with the right wait and the right day.