What is a commercial program? Presumably one that is written and sold for gain. We expect a certain polish from the games we buy, together with a professionalism that should mean that it is free from bugs and is also good value for money. Sadly, this is not always the case, some notable adventures have bugs, others are not worth the money we pay for them. Most of the time we grin (or grimace) and put up with it. We still end up with another adventure to solve and even the worst usually have something in their favour.

I have just played a game that is excellent value for money, does not appear to have any bugs in it, is fun to play, has a reasonably logical plot, can barely be classed as commercial and will keep you guessing for hours.

Bestiary is written by Perry Williams, uses Incentive's Graphic Adventure Creator (for the CPC version) and costs £1.50. You will not find it in the shops as it is a home-produced effort and is only available by mail order.

You play a young prince. Your greatest love being to read the ancient bestaries where you have learnt, much about strange and often legendary animals. All is well with the kingdom, until one year when a strange blight afflicts both the crops and the animals that the land desperately needs for its existence.

First your brother and later your sister leave the palace in search of a solution. Neither return. Both had been optimistically sent on their way with great celebrations by the king and his people. When you propose to follow in their footsteps, not even the king (your father) has any great hopes of your success and you leave quietly, unacclaimed and ill-equipped.

As you travel you will meet many creatures, some friendly, some not. You must find ways to get their help or at the very least something to distract their attention whilst you pass. The CPC graphics (by Rose Williams) are well up to any other GAC standards and the text is well written. A well produced, novel adventure. Buy it - you will certainly not regret it. Perry will even send you a hint sheet on receipt of a stamped addressed envelope. But be careful in reading the hints, they are a little too specific and may spoil your fun if read too soon.

Bestiary is available from: Perry Williams, 12 Goresdone Road. Cambridge CB5 8HR at £1.50. A PCW version can be obtained from Advantage, The Independent Computer User Group - telephone 0844 52075 for prices.