State machines
Shift-queued orders and an attack-move that fights and then keeps going
Players give a squad a chain of orders and expect it to march, fight whatever it meets and carry on. The usual bug is a fight that eats the rest of the chain, or a new order that cancels everything when it should have been added. Here is the order list that behaves.
One player ignores the match-found screen and everyone else loses their place
A match is found, but one player never presses accept. If everybody has to queue again from the back, the people who did everything right are punished. This entry shows who gets a penalty and who keeps their turn.
My character snaps back a few steps whenever the host corrects it
The game answers instantly on your screen, but the host sometimes disagrees, and the correction drags you back or makes you stutter. This entry shows how to take the host's word without losing the moves you made since, and when to ignore tiny differences.
A dropped player keeps their place, but not forever
A short disconnect should not cost someone their spot, yet a flaky connection must not freeze the whole team again and again. This entry shows how to hold a place fairly and when to finally give it away.
A player who reconnects sees a world that no longer matches
After a dropout the returning player either misses things that happened meanwhile, or gets flooded with a long replay of all of it. This entry shows how to pick between catching up on what was missed and sending the whole picture at once.
A rematch button that starts with half the group or never answers
After a match everyone is asked for a rematch. Someone says no, someone leaves, someone just does not answer, and the game must decide cleanly between starting again, shrinking the group, or giving up. Here is that decision.
Other players stutter and teleport instead of moving smoothly
You only get news about teammates a few times per second, so drawing them where the last news said makes them hop. This entry shows how to draw them slightly in the past so they glide, and what to do when the news stops coming.
A tech tree where some techs need all parents, some need any, and research can be switched
Research screens look simple, but the rules behind them are not: what counts as unlocked, what happens to half-finished work when the player picks something else, and what to do with points left over when a tech completes. Here is one set of rules that holds together.
Two queued buildings both count on the same gold
The player queues several buildings while the treasury looks fine for each one alone. Then the first starts and the others fail, or worse, all start and the treasury drops below zero. This entry shows how to keep a promise about money.
Respawn waves that make some players wait ten seconds and others none
Everyone comes back together at fixed moments. That is great for teamwork, until someone falls half a second before a wave and spawns into the same fight they just lost. This entry shows a rule that stays fair at both extremes.
A teammate is revived at the last second and dies anyway
The rescue bar fills while the countdown to death keeps running, so a perfectly timed save ends in a defeat screen. And when the rescuer gets hit, who loses what? This entry settles the rules so the save feels fair.
Houses lose their road link when one piece of road is removed
Whether a building is connected to the market is not a property of the building but of the whole road network, and it changes when a single tile goes. This entry shows how to decide who is cut off, and why diagonal neighbours and the first tile matter.