Shanghai is one of the first video game adaptations of the tile-based game played with the Chinese mahjong stones. Essentially, it's a puzzle game that has little to do with real mahjong rules.
The gameplay involves removing 144 tiles by matching them into pairs. The tiles are arranged in a gridded pattern, with higher levels near the centre. A tile can only be removed if it has no tile next to it on at least one side.
This computer implementation features a random board layout and includes five preset challenges, some with time limits of five or ten minutes, as well as a multiplayer mode.