Programs of this complexity never cease to amaze me. A fully implemented chess program at this price has to be excellent value.
Good graphics, 10 levels of play, options to set up particular games, recommended moves from the computer when you get stuck, and a clock to prove to you just how slow you are: the list of features is seemingly endless.
The program is suitable idiot-proof, which is just as well when I'm playing. Even on the simplest
level, it's fascinating to use the computer's recommended moves and analyse why it recommends them.
I'm not sure how a Grand Master would react to this program, but for ordinary mortals who want to practice, improve, or simply learn together with the Spectrum, this program makes an ideal partner.
You can't make illegal moves, you're never hurried by an impatient human, and even if you get stuck, you can get some help quickly.
A superb example of a real application for a home computer. Also available under the Sinclair label through Psion.