GNU Chess is a free software chess engine which plays a full game of chess against a human being or other computer program. The goal of GNU Chess is to serve as a basis for research. It has been used in numerous research contexts.
The game has no real narrative. The introduction simply places the player in the role of an unnamed explorer who must delve into a subterranean labyrinth to locate 11 hidden treasures and return them to the surface.
In Bridge to the East you have to collect crystals and protect something (e.g. a hut) from birds, bugs, stones and other things so it doesn't get destroyed as it contains a valuable gem. After each level (4 in general) comes a riddle you have to solve.