Think of the best computer games you know. What features do they share? Good graphics, of course. Colour, sound, speed, naturally. But surely an essential feature is a constant, demanding interface with the machine. And watching a horse race just can't count as that.

Excellent music introduces you to the racecourse. You are then presented with a portrait of a bookie called 'Honest Clive Spectrum' - though he looks too happy to be really happy - and you are of course invited to bet on a field of amusingly named nags.

Up to five punters can lose at once, and there is an ingenious choice of different betting systems available. Your ditherings are accompanied by the sharky smile of Honest Clive and a pretty good representation of the horses trotting around the enclosure.

Once you've bet, your active participation is over, and more good music accompanies a view of the field poised to go. The starter drops his flag, and they're off. The display of the race has to be good since the player now has nothing to do but watch it. In Derby Day, it's adequate.

The horses gallop in a jerky slow motion across the screen, the dead-straight track scrolling left around them. There is some attempt to convey the thunder of hoof-beats, and the race is watched by amusing groups of spectators.

Problems arise, however, when the horses reach the home straight. The cassette insert claims that this part of the race is displayed in slow motion. What this means is that the scenery stops moving. The horses actually go slightly faster.

The winning horse is named and there are occasionally photographs for places.

This isn't an original idea, and not one that seems particularly suited for a computer game. The music is good but the only commendation I can think of is, it will please people who like this sort of thing.