Computer games are loved for many reasons, but the overriding attraction is that while engaged, the player is transported toa place in his or her mind where just about anything is possible.

Wartime Germany or modern day middle east can be bombard utilizing period technology to the full, new worlds can be explored in the Space Shuttle, mythical lands exorcised of demons and the wave of a hand and the cast of a spell, and motor racing circuits can be created and raced around at break-neck speeds.

Shuttle, Wing Commander, Legend of Kyrandia, Project X - the names are all strongly suggestive of action, intrigue and adventure, which is precisely what we gamers crave. Call a game Puddle or Cheese Plant and it just doesn't conjure up the same image.

Similarly, if it's a crazed and frantic contest that you're after, then an affair called Walker isn't necessarily going initiate an adrenalin flood, because lets face it - unless you own a pair of stout shoes and a durable nylon rucksack, walking simply isn't very interesting.

Names can be deceptive though - I remember shortly after beginnign high school, I picked a fight with a lad called Hillary; he gave me the drubbing of my life and taught me a valuable lesson in presumptuousness. By the same toke, far from being a dull and boring one-leg-in-front-of-the-other-'em-up, Walker is in fact a shoot-'em-up, and a bit of a stonker at that.

Sometime in the near future, law and order throughout the world have broken down. Due to rapid technological advances, enemies are able not only to destroy each other with what have become conventional weaponry, but can eliminate entire forces by travelling backwards and forwards through time in massive time travelling weapons - a la Back To The Future - and destroying their ancestors, thus ensuring their foes were never born. By Jove!

The flagship of this curious clock-defying army is the AG-9 Walker, a ten metre-tall heavy duty tank on legs that - if tanks broke sweat, which the obviously don't, but if they did - could annihilate a city without spilling a single salty bead.

You take charge of the Walker as it stalks through four different points in time, seemingly forgetting its mission and destroying every single thing that moves. The enemies vary according to the point in time which you currently stand (or walk - guffaw!): Lancaster Bombers and Army trucks lead the bombardment in the World War One stage; space-age vehicles take over the mantle of the Future level, and a whole array of semi-modern pieces of kit comprise the middle two levels - the Urban and Industrial time points.

Having mentioned it earlier on, you may now be wondering quite how a shoot-'em-up featuring a "tank on legs" could work. Very simply, is the answer. Unusually, the screen scrolls from right to left, and the Walker is controlled by a combination of the mouse and keyboard. The cursor keys (or certain letter keys) are used to move big W backwards and forwards, while the mouse comes into play to manipulate the weapons.

The Walker itself is a pleasure to watch. A massive 81 frames of animation ensure that every move it makes is impressively smooth as it stomps its way to destruction. Enemy characters are contrasting - most (with the notable exception of the level guardians) are quite small and plain in colour - but the animation, both of these and of the atmospheric backgrounds, are such that the two styles complement each other well.

The backdrops also change in accordance to the time frame, and the number and speed of the enemies ensure that boredom will be a long time in setting in. What helps Walker really stand out from the crowd though, is the sound. Seldom are you likely to hear more realistic or fearsome in game samples as these, and the pumping intro tune (seven minutes long!) does an excellent job of creating an atmosphere conducive to killing.

When we previewed Walker a couple of months ago, it was thought that there would be the option to actually control the machine from inside the cockpit. Three isn't and having seen the game it becomes obvious that an attempt at implementing this would spoil the game.

Developers DMA have managed to combine the best elements of several games in coming up with Walker - a tough, fun, addictive and original shoot-'em-up that oozes quality and spews out action like there's no tomorrow.

Power-ups would have been nice, and a pause option wouldn't have gone amiss, but this is a great release from Psygnosis - a real tension reliever.

From the Encyclopedia Parallalelium ('builds week by week into a pile on your carpet'), three extracts on the great war:

1. THE HISTORIAN'S VIEWPOINT
With the advent of time-displacement equipment, mankind reached a new level of madness. Temporal war wrecked the past as opposing sides struggled to undermine their enemies by planting bases further and further back in history. Transporting enough troops to combat this threat through the time gates proved to be an impossibility, so the Walkers were devised. These huge armoured machines were each piloted by a single, dedicated soldier, each one desperately trying to turn back the tide of the enemy hordes.

2. THE SOLDIER'S VIEWPOINT
War is hell? Who ever sad that, man? War's only hell when the batteries go flat on your Walkman, and don't you forget it. Mess with the best, die like the rest, in war the first casuality is everyone else, an' that's te truth. In times like these, I quote Ferris Bueller quoting John Lennon: 'I don't believe in Beatles, I just believe in me.'A good point there - after all, I've got dual 50-calibre cannons.

The rules of engagement are pretty simple. One- cut no slack. Two - take no crap. Three - kill all prisoners. Time wars aren't so bad, I suppose. You get to travel lots and the hours are pretty good.

I like my uniform, the pay's not so hot, but I just luurrrve my walker. Just look at it, man, is that bad or what? When ya see me an' my gleaming blue beastie comin' down the street, don't even bother running, you'll only die tired. Is that cool? Am I a heartbreaker an' a life-taker? You betcha, I'm a certified stone-cold killer, an' I've got the papers to prove it.

I'm telling' ya cuz, I'd cus my mom out for the sheer heck of it. An' stories. I've got THIS many of 'em. I remember back in '57, it was a real helistorm. The bad guys just kept on comin', man. I really thought my gun-barrels wuz gonna burn out, but eventually I ended up killing so many it wasn't even funny any more. Life's like that.

3. THE REVIEWER'S VIEWPOINT
Takka-takka-takka-BOOM!! Die, verminous hang-gliding scum! Eat cannon fire, mutoid bikers! Just three of the many things I've said during numerous games of Walker, and to dispel any false notions yo may have about the game: it has no strategy, it has no variation, it's not the official game of the United Nations. It's great.

You control the walker through four time zones, each consisting of two levels, and you kill things. It's as simple as that.

Unusually for shooty game, you use the mouse to direct the targeting monocle around the screen, and use either the arrow keys (or Z and X) or a joystick to move the walker across the screen. This works fine with a Bug joystick as you can hold it in one hand, but for bigger ones, you'd better stick with the keys.

On your side, you have a 40-foot high walking robot, with your pilot stuck away safely in its head, his itchy and slightly sweaty thumbs on the fire buttons. Against you is ranged a sizable proportion of the Great Armies of Our Time, ranging from WW2 vintage, through modern, post-apocalyptic and futuristic nasties.

Regardless of their position in time, it's up to you to make them all history, by either blasting them into small bundles of bloody rags or, for the sake of variation, stomping all over them and treading them into the ground.

Needless to say, your enemies aren't going to take this sort of abuse lying down, and there's almost no limit to the methods their attacks take. From the ground, soldiers jump out of trucks, motorbikes drive by, human waves stand around waiting to get chopped up by you, and trains chuff merrily along.

Occasionally a particularly determined guy will try and plant a bomb on your powerplant by climbing a rope, but you can usually shake him off. From the air, paratroops descend, choppers flit around, hang gliders drop things on you and strange futuristic 'things' do strange, futuristic things. There are even attacks from off screen, with bombers raking the screen from (persumably) several thousand feet, their passing marked only by a laser-sight appearing on the ground, and a huge zeppelin makes brief appearance just long enough to explode in one of the meatiest 'Whumphs' in video game history.

You only get three Walkers, each of which is protected by a pretty flimsy shield, so you've got to keep on your toes and run around avoiding the worst of the incoming artillery. Also, there's no point in spraying the kill-zone with indiscriminate fire, as your guns quickly overheat and jam. And you just kill everything, except for the little horses that wander around, get in your line of fire, and generally make you feel bad every time you off one of the little darlings (as well as costing you energy).

Such a simple, and some may say boring, concept is brought to life by some awesome graphics. The Walker itself boasts 81 frames of animation, so just about every conceivable head position is covered, and even though the soldiers are tiny, they blow apart most impressively in a spray of visceral gore.

Also, vehicles don't just vanish when you blast them, instead you've got to reduce them to increasingly twisted hunks of junk to clear the screen.

The sound's brilliant, with screams, gunfire, ricochets and even a tiny little speaker playing boppy tunes from a chopper's radio as it fires off rockets at you. Cranked up suitably loud, you get that 'warzone' feeling, and only the inclusion of a free napalm-scented scratch 'n' sniff card and your neighbour firing an AK-47 over your head could possibly increase the feeling of really being there.

For the sake of objectivity, it's time to wrap up some criticism, but since I lover everything that's in the game, I can only really comment on what's not. The major downer is that there's virtually no attempt at variation in gameplay, with every level consisting of you blasting your way through to an end of level encounter (the platform section which originally alternated with the shooting bits in the game has been scrapped).

In fact, that's the only downer I can think of, although it's kind of an important one. I mean, for thirty quid you might be expecting more than eight levels of pretty much the same thing. This said, I can't see that many people will be howling for their money back, as there's a lot to be said for this kind of slick, polished, high-class slaughter. It really is my kind of fun.

Now, where did I put that magnifying glass, there's some ants on my window sill, and the sun's just come out. (Fade to maniacal giggling...)

Let's face it, good shoot 'em ups on the Amiga are a rarity these days. Activision's conversion of R-Type 2 was a competent enough blast, but moved at a snail's pace when the screen got too crowded. Then there was SWIV, which was fun while it lasted, but the difficulty level wasn't nearly tough enough. Only Team 17's Project X, with its arcade quality graphics and gameplay, really cut the mustard in recent times, and then it was so incredibly difficult that I bet few of you have progressed past level two even now! So it's encouraging to see no lesser talent than DMA, the people who brought you Lemmings, getting back to their roots and having a bash at coding a new blaster.

The result of their endeavours is Walker, a fast-paced shoot 'em up which puts you in control of a 30-foot human killing machine code-named the AG-9. Looking like a cross between ED-209 from Robocop and the huge mechanical transports seen in the Return of the Jedi movie, the towering machine is capable of spewing out an endless torrent of death from its twin machine guns mounted beneath its swiveling head.

The dodgy sci-fit plot involved some nonsense about two warring factions attempting to destroy each other by travelling through time and wiping out each other's civilisations. Leaving logic and the Space-Time continuum aside, it's not the most stunning excuse for a bit of blasting I've ever read, but does give some variety to the proceedings as you blast your way through four different time zones.

EXTERMINATE, EXTERMINATE
The aim of the game is simple: guide your Walker assault vehicle across a horizontally scrolling landscape blasting as much military hardware out of the skies as possible, while also taking care of the assorted ground battalions, mortar emplacements, tanks and other such obstacles. While not sounding very innovative, it's the pace of the action that makes the game such a winner - it just doesn't stop for a second. As soon as you've cleared one screen you're right back in the thick of things as another legion of enemy sprites charge at you.

The Walker pod and the innovative control method are probably the game's most impressive features. More than 80 frames of animation have been used to depict the Walker, an impressive mechanical behemoth with two huge gun turrets mounted underneath its swiveling head.

The high-tech beast is controlled by a combination of mouse and keyboard controls which might sound complicated but, in practice, they work a treat. Two keys control the backward and forward movements of the Walker as it moves about the screen while the mouse controls an on-screen crosshair.

A click on the left mouse button unleashes a volley of shots in the direction of the crosshair, while holding down the right button locks the targetting system on anything that is near at the time. This is a much-needed option, as manually tracking some of the faster-moving enemy sprites is damn near impossible.

It's not just a fire-and-forget type game, though, as the machine guns can overheat and close down if you use the continuously, so short rapid bursts are the best way to make progress. There's also an energy level which decreases depending on the amount of enemy fire you soak up. This starts at maximum strength, but quickly takes a nosedive, so you can't just wade into the enemy and try and stomp them underneath your huge mechanical feet. It's best to try and keep your distance and pick off the enemy sprites as soon as they rush onto the screen.

FOUR-WAY FIRE
In all, there are four levels to complete, each made up of two stages. These were to include a blasting stage and then lead into a Prince of Persia-style runabout where you'd dismount from the Walker and pick up new ammo supplies and energy pods. Unfortunately, the latter elements of the game have been dropped in favour of cramming in more blasting action, so the second stage of each level is just more of the same. Good though it is, it can get quite monotonous at times and the runabout stages would have helped break up the action quite nicely as well as presenting more of a tactical challenge.

Another quibble is the lack of any kind of power-ups or add-on armaments. It's alright having an endless supply of small arms fire but where are the triple-way fire, smart bombs and bolt-on lasers? Merely slugging it out through each stage from a showdown with an end-of-level guardian gets a bit boring after a while, especially as the opposition possesses far greater firepower than your trumped up pea-shooters.

I'd also question the difficulty level in places, especially when the screen is flooded with airborne-gliders - it's almost impossible not to sustain crippling damage under such an attack. Thankfully, you begin the game with four lives and each stage has a number of restart points, but even so it's a bit on the hard side.

Walker is a curious game in many respects, but the weirdest thing about the game is that it actually works better on a bogstandard A500 than it does on the A1200. The faster processor of the latter machine makes everything move just a little too fast. The ground troops rush onto the screen at warp factor nine and the airborne vehicles swoop down onto the Walker like some sort of bird of prey.

On the A500 things quieten down a bit. Don't get me wrong, it's still fast and furious, but it all seems a little bit more realistic. The A1200 plays like one of those black and white movies that's been speeded up with the cops and robber charging about the screen like there's no tomorrow.

SONIC SCREAMS
The in-game sound effects are just brilliant. The mechanical clunking noises as the Walker stomps across the screen are excellent, as is the rattle of the twin machine guns as they rake the landscape. Then there are the screams of the snipers as they fall to their death and the droning sounds of a squadron of bombers passing overhead.

The first level helicopters fly onto the screen with Little Richard's 'Long Tall Sally' blaring from the speakers in a tribute to Arnie's Predator movie. A lot of effort has gone into the samples used in the game and it adds significantly to the on-screen action.

The game's graphics are also a bit darned good. Although the miniature foot soldiers resemble Spectrum sprites at times and are even tinier than those use in Lemmings, they move realistically about the screen as they check their positions and run for cover once you left off a volley of shots in their direction.

The war-ravaged scenery is quite spectacular, although the difference between levels isn't that noticeable - one partially destroyed tower block looks suspiciously like the next, no matter which time zone you're in.

Where the graphics truly excel is in the depiction of all the various bits of military hardware, from the mortar emplacements and motorbike riders through to the armour-plated tanks and troop carriers to the absolutely huge Zeppelin that hovers ominously in the sky. The attention to detail is staggering and the copper effects used to illuminate the sky help lend an eerie look to the proceedings.

All in all, Walker is a more-than-competent blaster with a novel control system and some fast and frantic gameplay. A few tricks have been missed that could have dramatically improved the game, but you're still left with one of the best shoot 'em ups we've seen in a long, long time.