Gorf is an arcade classic available to Vic owners on a reasonably priced cartridge.

The attraction of the game is that you get four shoot-'em-ups on the one program, thus giving you a certain variety in your zapping.

The first of the screens is an invaders-style challenge. 'Mission 1', the message reads, 'Astro Battles, Separating your laser base from the invaders is a curved force-field.

You have to blast a few holes through this in order to get a shot off: the danger, of course, is that the aliens can get a shot back at you. The firing too is slightly different from the norm; you cannot fire a constant stream, but must wait until a bullet has hit its target before firing another.

This is, in fact, an advantage rather than a drawback, making the game much more challenging. It's a tricky business dodging the invader's bullets, especially when it gets down to the last one zooming frantically across the screen. Bonus points can be scored at this stage for hitting the red mother ship which floats across the top of the invaders.

Once you've got rid of these rascals, you move on to Mission 2 - Laser Attack. This screen is a Galaxians variant with two groups of aliens, one at each side of the screen.

In each group the lowest bird-like creature fires a very nasty laser bolt which spells death to all who get in its way. As well as avoiding this thing you also have to get out of the paths of the swooping Galaxians.

It's not easy. But in time you'll master these vicious blue and yellow creeps and graduate to Mission 3: Space Warp. Here the screen displays a number of pulsating colourful lines radiating from the centre of the picture. Tiny ships appear, speed toward you getting larger and then drop their vicious bombs on you.

To succeed here you need nerves of steel and an eye sharp enough to get the ships in their infancy. If you've got what it takes you will eventually reach the fourth and last screen: Flagship. Once again you are protected by a force field but this time you must try and blast the spaceship cruising overhead. Naturally you are under constant attack from the ship's bombs. The difficult thing here is to score the required direct hit on the flagship's central power supply.

It demands art exact sense of timing which I have yet to master. Given the limitations of the Vic as a games machine, Gorf's graphics are impressive. The sound is also quite good with suitably loud zapping noises. At £10.00 for a cartridge, Gorf is very good value indeed.