Clockwork Orange Chess is based on the 1971 movie A Clockwork Orange. In this movie, a young hooligan named Alex is released from jail after being conditioned to feel ill and nauseous at the thought of commiting violence. The idea behind Clockwork Orange Chess is that the same conditioning process is used on captured pieces. Captured pieces are replaced with non-capturing counterparts and given back to the player they were captured from, who holds them in hand until choosing to drop one on the board. When a non-capturing piece is captured, it gets replaced with a regular piece. This provides an incentive to not capture non-capturing pieces.
Zillions needs lots of thinking time to play a good game. It didn't beat me at the game until I gave it one minute of thinking time. However, I have since beat it even at one minute.