Professor Potts has a little problemette. While he was working on his time machine terrorists attack, smashing his temporal moped and whisking him down the time lanes into prehistory, to a time so long ago he'd have to wait 10 million years just for Racquel Welch to get her fur bikini out.

Luckily, he'd tucked five teleporters and a stun gun in his pocket before the attack, with which me must find his way back to the present. The solution is not so much revolutionary as evolutionary: by guiding the lifeforms he encounters, he can open the right time corridor and get himself home before he left!

The five zones include 1 million years BC, when the dinosaurs ruled the earth, the Ice Age and the Middle Ages. In each he must alter the status quo so that evolution takes its course. Successful completion opens up a time lane forward to the next stage.

Each task involves giving mother nature a nudge in the right direction. In the prehistoric zone the job is to ensure mankind actually happens in the first place, while the resultant cavemen need a little advice on the tech spec of the wheel. To lend a hand the Prof has to teleport and then move objects into new places so the inhabitants get the idea.

Move the right ones and the zone indicator flashes from red to green. What's more, when the majority of the current level has been correctly altered the next age is accessible.

The central paradox of Time Machine stems from the fact that even when something's fixed, it's not. At any time it can revert to the old state, which threatens any future dependent on this earlier time for existence. Using an on-screen zone indicator Prof Potts has a view of all the 25 areas he controls. If something goes awry he has to leap time and fix it. A more of the future opens up to Potts, like a plate spinner, he must try to keep the earlier ones safe.

The professor has three lives and little energy. His life force is sapped by standing in puddles of ice water or being blatted by a volcanic fire and is refreshing by eating any fresh fruit he finds. The only time limit is that of time itself. Confused? You will be.

GRAPHICS AND SOUND

Time Machine is a cartoon adventure packed with cute creatures, caricature people and comic historical backgrounds. The godlike Prof moves in a slightly mysterious way and takes some joystick practice to control, but does everything required with a quick waggle. The limit of only five screens per time zone is no drawback, because you see it five times over the millennia. The 25-screen indicator makes every zone easily monitored, if not controlled. The tune's a cute overture that demands shutdown after a few minutes, or changing to the effects option at the first opportunity.

LASTING INTEREST

The puzzles which free up each respective temporal zone are reasonably obvious, but it's the changing and keeping them that way which is really hard. It's all too common to be virtually home and have a hundred thousand years of hard toil spoiled in seconds. It's a chronological balancing act and that challenge remains, regardless of previous success. A real hair-tearer, Time Machine is relatively finishable in theory, but we all know what a complex theory relativity is.

JUDGEMENT

Time Machine is not a big game but a clever one, packed with playability and originality. It will have you chasing over hill and dale madly plugging holes in the temporal stream, but there's actually too much time to cover and not enough Professors. It gets under the skin by appearing feasible, even easy, then proving to be exactly the opposite. Nothing, not even the most advanced technology, staves off the ravages of time,

They don't make 'em like this any more, well most software houses don't, they're too busy designing cyberspacial realities created from filled polygons rotated in realtime. Vivid Image, who appeared on the scene with the eclectic Hammerfist early this year, create the kind of software that eight bit gamers used to fill for: pretty, polished arcade adventures.

In fact Time Machine does make one grandiose claim - that it's a 4D fantasy role playing game. The fourth dimension as every hot young physicist will tell you is time, and in a sense it does fulfil its boast.

Time Machine concerns a dotty scientist in the Emmett Brown mould who is knocked back into prehistory when a bomb explodes near his time machine. You have to manipulate history and time to return to the present without disturbing the natural progression of things. To do that you have aid the planet to heat up or cool so the animals you find can evolve.

You start off in the year 10 000,000 BC and as the game commences you find yourself on a plain surrounded by flaming eruptions. The game is based around a five by five matrix of screens and time zones, that's five different screens set over five different time zones, through the ice age and the stone age, to medieval times and the present. The solution to each period doesn't necessarily exist in the same time zone, so you have to manipulate the prof backwards and forwards.

You're helped by teleporters, which you can drop around the screen, and which enable you to transport between screens with ease, which helps you no end when you're faced with swamps and rivers. Potty can also jump, pick up objects and stun things with a beam he carries about. He can also suffer a grisly fate so you have to be careful with him. He can drown if you're not careful and his energy is depleted when he's hit by objects - like hot lava which the volcano on the first level spews into the atmosphere at regular intervals.

Time Machine is a neat little game. Its graphics are pretty without ever looking stunning, and its sound effects (we'll forget the awful tune) add to the atmosphere of the game. Most importantly it's fun to play - the challenge it sets is uncomplicated without ever being easy, something several games released over the last few months would do well to remember. That's old-fashioned values for you, though.

At the beginning of Time Machine someone has interrupted the appliance of science with the appliance of a large explosive device. Professor Potts' chances of winning the Prince Charles Design Award with his environmentally friendly, pastel coloured Time Machine have gone up in smoke. The Prof got caught up in a terrorist attack; an explosion hit the machine and destroyed the Accelerator Crystal. This little Semtex shock has launched poor Potts 10 million years in the past.

In order to return to the future, the Professor must first create it. There are five zones to create: prehistoric, ice age, stone age, medieval and modern. Each contains five screens which must be adjusted to get the next stage of evolution underway. Travel between screens and times is achieved by using special travel pods but there are a limited number of these so at times it's back to good old shanks pony.

Once you've instigated a new era, you can travel freely between it and the past. You'll have one eye cast on the future but you need another eye looking over your shoulder. The past is not a passive place; the tricks you've introduced can be overturned by inhabitants, plunging you back a few aeons to where you started.

Having got as far as the future you've then got to stop history repeating itself. This means finding the crystal, installing it in the machine and getting away before the terrorists get to you. If this doesn't work out then you'll have to develop a taste for pterodactyl eggs.

Paul: Time is a jolly strange business. Unlike Thyme. Thyme is really simple, adds an interesting flavour to casseroles and doesn't threaten to whisk you 10 million years into the past. Perhaps that's why no one has made a cooking sim or a vegetable shoot 'em up. Let's face it thyme is actually rather boring. So let's turn our attention to time and stop wittering on about cookery.

The first thing you notice about Time Machine is that it would be of little use in the kitchen. For starters it's too big to fit in a saucepan and secondly, even if it did fit, the flavour of engine oil would be a little off-putting.

However once your editor has started threatening to sack you if you don't get on with the review you start to notice other factors like... the loopholes in your contract fr'instance and... er... Time Machine's beautiful graphics. These really are outstandingly colourful, well drawn and even a little cutesy. (Ahhh.)

Each screen is worth looking at. Considering that there are 25 of them it's very impressive that the game works on a single load. This means once the game has loaded at the beginning there is no waiting between screens to upload the next screen. Very useful when you're having to jump about through time and space.

Time Machine is also very playable. The controls are straightforward and accurate which is quite a relief, you don't want to make a bodge of evolution just 'cos you were too clumsy.

Despite its obvious strengths I'm slightly worried that Time Machine falls between two stools. The puzzles aren't sufficiently obscure to make it an effective adventure yet there isn't enough 'danger' in it to make for an arcadey game. However it's an imaginative, well executed and very playable game. Well worth a look.

Can't afford, or find a chrono-charged De Lorean? Never fear, Prof Potts has his own means of travelling through time, with a machine in the classic mould of HG Wells's device. The only problem is the Prof likes to work outside, and as he's about to zip off to one million years BC (and meet Raquel Welch!), terrorists strike!

The explosion destroys the time machine and its vital accelerator crystal, hurling the Prof a lot further back in time than he'd intended. He arrives in an era when humans have yet to evolve. The future as the Prof knows no longer exists. So he must alter history to recreate the 20th century, allowing him to prevent the terrorist attack and live happily ever after!

Prehistoric Times comprises five flickscreens, including a swamp, river and volcanic ground. You must find a way to cool the Earth down, killing off the dinosaurs, and allowing humanity to evolve. If you do this successfully another Time Zone is created, the Ice Age. Here you must find a way to heat the planet up. In all, there are five Time Zones with the Stone Age, Middle Ages and Modern Day. This makes a total of 25 screens, shown in a grid at the centre of the control panel.

Once a Time Zone is created its five screens turn blue and you can travel there: you stay in exactly the same position as you were before, only the time changes. Often landscape features such as rocks and trees are still there, the river is in virtually all Zones. Potts also carries Travel Pods which can be dropped and teleported back to.

All this time-travelling is crucial because you could be in the Middle Ages when the Ice Ages stop heating up, threatening Man's evolution. So you must warp back and fix the problem before all the Zones collapse, sending you back to the start minus a life. You might also need some food which grows in Prehistoric times, or need to change an object which will have an effect on a later level. Your energy is shown by a gauge on the right of the control panel: energy is drained by walking underwater (!), being hit by objects such as falling icicles and being hit by creatures such as yetis! To defend yourself you're armed with a short-range zapper; initially it stuns a creature (useful if you want to pick it up), but prolonged fire might kill it.