DEEP plots are usually few and far between in the gaming world. Unless it involves submarines, of course. The plot of 688 tends to concentrate on the latest in technical gadgetry rather than the humdrum mechanics of submarine piloting.

You have many different types of map display, ranging from a overhead view with several levels of zoom, to the latest in high-frequency contour mapping systems which will produce a wireframe version of the seabed around you.

The periscopic-view graphics have either been digitised or brilliantly drawn. They aren't animated, more sort of redrawn for each new shot. This takes a second or so, but whenever you surface among a convey of destroyers and the helicopters start buzzing you, that one second delay is the only respite you'll get.

Images of the crew members are definitely digitised, and what a grumpy looking bunch they are. They didn't even cheer up when I gave them a week's leave in San Francisco.

The best way to make your sonar operator happy is to deploy a towed array of hydrophones to let him listen out for approaching craft. You can help him even more by selecting high or band pass filters and performing a frequency analysis of the incoming signal.

Once you have a fix and move within range, you can release your torpedoes or launch a couple of surface-to-surface missiles. For the sake of improved gameplay, the temptation to use nuclear weapons has been removed. There aren't any. Good Show.

A slightly less moral problem facing all simulation designers is that of choosing a realistic time rate. A real torpedo might travel for upwards of 30 minutes, which would drag a game out for days. Conversely, a helicopter might fly overhead in a matter of seconds. This means that simply compressing time is not an option.

The best solution, according to the creators of 688, is to fiddle the figures. And why not? The result is a fast-moving, exciting challenge that all simulists will enjoy.

The 10 missions can be played using either the American Los Angeles or Russian Alfa class of sub. For some reason the Russian subs are all slightly less well equipped and more grimey looking than they American ones.

At least the options are in pseudo-Russian, which just about makes up for it. A few years ago, getting to play a Red wouldn't even have been implemented. If you have only been interested in flight simulators before, perhaps now is the time to try a different challenge - about 1500ft under water.

MicroProse have had things to themselves for a long time in the submarine market: their aged game Silent Service gave the player a chance to experience the thrills and spills of captaining a World War II sub. Now Electronic Arts bring things right up to date with a simulation of the latest range of American and Soviet subs.

It is mainly a one player game, but on some missions two players can play head-to-head via modem, each controlling a different side's sub. There are 10 missions in total (although the first is merely a practice mission) which may not sound like much but, as anyone who has played this sort of game will know, one mission can last a very long time. Moreover, once you have played them in the American sub you can play them again in the Soviet one, effectively doubling the number of missions.

The whole game is played and controlled from a main screen depicting the inside of your sub. By moving the mouse over certain members of your crew and clicking, you reveal different areas of the sub. The areas include the radio room where orders are sent and received, the navigation room where waypoints and so on are set, the engine room, torpedo control, damage control, the sonar room and the periscope. Obviously, the options available in each room vary, but the act of switching between rooms simply involves hitting a function key.

Once you have got your order and have decided on a strategy the first thing to do is jump from room to room and complete all the necessary tasks. Then you can switch on all the latest gadgetry (things like the contour computer, which gives you a constantly updated image of the surrounding sea bed) and settle back for some nail-biting tension.

GRAPHICS AND SOUND

Well, you cannot expect brilliant sound, can you? The few spot effects that are there are fine. The graphics are much better and everything has been well drawn: the few little bits that are animated, are animated well.

LASTING INTEREST

The missions are timed, which some will see as a good thing and others as bad. With about 20 missions for the solo player there is plenty to keep you busy.

JUDGEMENT

You have to be a certain kind of person to enjoy a sub-sim: someone who likes to think about their actions and does not mind waiting a few minutes for things to happen. Sub sims rely on building tension and 688 does it beautifully. A great example of the genre and a brilliant game to play with a remote friend via a cable link.

If you are one of those people who thinks that a sub is a loan you get off a Cockney, then you probably think that submarine simulations are dull and boring. Think again. Not only does 688 A.S. have enough trigger happy action to keep you happy, it also has a depth of playability that even HMS Conqueror could not match.

I do not care what the Admirals of the world may say about the submarine's surveillance and stealth capabilities, to me, a sub has always been a big grey thing that pops out of the water occasionally and kills everything in sight. The game does not claim to be an accurate simulation of the U.S. 688 and the Russian Alfa class subs. But it certainly gives the impression of being an accurate insight into the workings of a sub, showing you exactly how to assault and how surveillance missions are carried out.

As Captain of either of the two submarines, you have to complete a series of missions, ranging from the small, such as shaking off an opposing sub, to full scale participation in World War III.

The game is controlled from the main deck of the sub. You can move around to various stations by clicking on them and give orders to the crew. This is not as simple as it sounds. Just moving requires you to tell the navigator where to place waypoints and the pilot the speed and depth at which to travel.

Stealth is the name of the game. Attacking boats is a very tricky thing to do if you want to remain unseen, as you have to come up to 20 feet and raise your periscope to achieve visual confirmation. More often than not, an enemy helicopter will be waiting for you when you surface and will sound the alarm. Once your cover is blown, you are in trouble matey.

The graphics are brilliant. Almost all of the pictures in the game are digitised, and the view from the periscope when attacking ships can be very impressive indeed. The animation rate is low as are the number of frames of animation, but with a game like this, who needs silky smooth animation?

The sound is stunning, too. All effects are sampled, and very atmospheric, though I am not too sure about the happy warbling speech giving you messages such as 'We've been hit! We're all going to die!'.

I had a lot of fun playing this and soon I was hooked. It is nowhere near as involved as Red Storm Rising, but it is an atmospheric product, and a highly exhilarating one at that. But I would advise you check it out if you are after something to tax the brain.