Toy Duel

2 players · 2 minutes · playable

Toy Duel is ours, invented as a test case. It is small enough to reason about completely and awkward enough to exercise the parts of the platform that are easy to get wrong.

How to play

1. A deck of cards numbered 1 to 10 is shuffled. Each player is dealt three; four are left over.
2. Both players choose a card from their hand and play it face down. Neither waits for the other: both decisions are live at the same time.
3. When both have committed, the cards are turned over. The higher card wins the round. A tie wins nothing for anyone.
4. Played cards stay face up. Hands are never refilled.
5. The first player to win three rounds wins the match. If the hands run out first, whoever has won more rounds wins; equal rounds is a draw.

Why this game exists

Everything about it is a test. The face-down commitment means the server must hold a card it will not tell the opponent about, and must still animate something, so a player can see that a move happened without learning what it was. Both players being asked at once means nothing in the platform may assume a single active player. The shuffle must come out the same way on a replay years later.

A game that only needed turns in order, with everything face up, would have let all three of those mistakes through.