Malevolence is a "Quilled" game, in which the death of your uncle prompts you to set out to restore the family fortune. A letter from your departed relative indicates that this may be done only by killing one of your uncle's old acquaintances.

Just in case you think that knocking off the old man's pal is a touch antisocial, I should add that the aforesaid acquaintance has fallen on hard times and is now a bit long in the tooth... and he will happily demonstrate the length of his dentures by sinking them into your neck. To wit, the old codger has turned vampish.

Malevolence has a great loading screen but is otherwise text-only. That in itself is no bad thing, but where Malevolence falls down - as do so many homebrew games - is in the quality of its puzzles and the style of the text. But let's not be too rude about it. Looking carefully at a game like this can teach us all a lesson.

The fact is that designing puzzles for adventure games is extremely difficult. Many adventure designers tend to construct puzzles on the basis of finding objects. For example, in this game there is a large spider which you can pass only by burning its web - hence you need to find some matches.

There are many variations on this "find object, solve puzzle" theme. Sometimes you'll have to find several objects and combine them to make another - there's an example of this too in Malevolence, where you combine different objects to make a fishing-rod, catch a fish, and use it to pass a hungry wildcat. Puzzles of that particular sort are quite common (making a blowpipe in Morden's Quest to kill the pygmy, for example) and can sometimes be extremely difficult as anyone who will remember making the sonic screwdriver in Ship Of Doom will recall.

A few "object puzzles" in a game is no bad thing, but in many homebrew games (and sadly in some commercial releases) that's all you get. What's more, they tend to rely for their difficulty on their obscurity - the only reason the sonic screwdriver baffled people was that no one in right mind would ever think of making one. However good they are, though, if object puzzles are all you get then the whole feel of the game suffers. Malevolence relies almost exclusively on object puzzles, and the effect is, in the end, to rob the game of any real excitement.

So what's a good puzzle? Well, to a large extent this is a matter of personal preference, but generally speaking a good puzzle will involve interaction with objects and characters in a way that reflects some of the frustrations we experience in everyday life - or, even better, invents new ones. For example, you can't lift a floorboard because you've forgotten to close the door, which has swung out across the board and is preventing you from raising it (see The Pawn). Or in Infocom's Ballyhoo, you can pass a guard only by imitating someone else's voice: the trick is to inhale gas and alter its tone.

That's not to say that object puzzles can't be great fun - the best example must be the Babel Fish in Hitchhiker's Guide To The Galaxy. Those of you not familiar with this puzzle should know that the fish pops out of a dispenser and down a drain. If you block the drain, it gets whisked away by a floor-cleaning robot, and so on. To get the fish you have to employ several objects at once. It's worth pointing out, however, that even this puzzle succeeds largely because of the humour of the text rather than the logic of the situation.

Malevolence has quite a few locations but here we come up against problemette number two - style and originality.

There are a couple of spelling mistakes in Malevolence, but these are really not a problem. What is a problem is that none of the locations shows a real sense of invention. There's a place with a big nasty spider - well, I'm sure we can all think of at least one famous adventure with nasty spiders in it. There's a grassy hill, a cobbled path, a little harbour with a rowing boat, a maze... All acceptable, but nothing that really zonks the brain with mind-blowing originality.

It's not all like that, thank goodness. There is an unusual underwater scene in a sunken wreck, but here we come across another stylistic error - inconsistency. There in the wreck, beneath the waves, is a book lying open on a desk. Now books simply do not lie open on desks in rusted hulks on the sea bottom. And if they do they certainly aren't readable. Of course they could be readable - that might make the basis of an excellent puzzle - but in Malevolence you just hold your breath, duck under, and read the book. Hmmm!

Mrs Page writes in the letter accompanying her family's game: "Are we wasting our time?" She and her family have been sending their game to software houses in the hope of getting it released. It hasn't been, and honestly I'm not surprised. But that's not a problem - of course you're not wasting your time! There's an enormous amount of satisfaction to be had out of devising these games instead of just being a consumer of purchased packages -and there will always be a friend or relative who will get a lot of pleasure out of solving them.

However, if you rely for your satisfaction on the wider public exposure that comes with commercial release then you must improve the way you think about puzzles, and develop more ideas like your underwater scene. You can get a lot of help in this from other adventurers - try joining a club like Pat Winstanley's Adventure Probe, dedicated to helping people write better games.