Shanghai is a really fun game mode and the rules are fairly simple.
Each player starts by trying to hit one number per round, starting on 1 and ending on 5.
Hitting a double and triple increases your score by that amount respectively.
If you manage to hit a single, double and triple in the same round, your score is tripled for this round.
The winner is the player who has the highest score at the end of 5 rounds.