All the standard chess pieces in Terror Chess move in the same way they do in normal chess. The additional pieces of the Cardinal, Marshall, and Terror are all well known chess variant pieces. The Cardinal moves as a Bishop or a Knight. The Marshall moves as a Rook or a Knight. And the Terror (a.k.a. the Amazon) moves as a Queen or Knight.
The idea behind Terror Chess came to me after playing some other large chess variants which used the Marshall and Cardinal with the standard chess set. Games like Capablanca's Large Chess--thus having pieces representing all dual combinations of the three basic piece movement types: bishop movement, knight movement, and rook movement. Terror Chess adds in the Terror, which combines all three movement types.
A ZRF file for playing Terror Chess with Zillions of Games is available for download here: