Keeping the countryside clean and pretty might not sound much of an excuse for a computer game. But when the countryside in question is the last remaining green and leafy bit on the whole despoiled planet, and there are veritable swarms of homeless aliens just dripping to get at it, you might see that it's not yer average park-keeping commission.

In keeping with the slightly untoward aspects of the job is the executive transport and alien-persuading gear you get along with the peaked cap.

Better even than a land Rover, the JOS fighter you fly is equipped with lasers and blitz bombs. Lasers are jolly good fun, but the blitz bombs are both deadly to an entire screenful of aliens and limited to 20 per life.

The aliens, by the way, come from what used to be a planet circling Cygnis Alpha when there was a Cygnis Alpha to circle.

But the star went supernova, turned into a rapidly expanding shell of excited gas, neutrinos and even more excited astrophysicists, and took the planets with it. The aliens want a new home. In fact, they want yours.

Your side-on view shows you flying forwards and backwards above a simple landscape, with the region you're in, the number of bombs left and general ship-like readings displayed below.

There are three regions to keep clear of xenobiological filth; one forested, one desert and one oceanic. Anyone remember UFO, with those wonderful underwater battles? Tsk. All too young.

Each region has ten zones. A zone is a self-sustaining area, kept clean of the surrounding degradation by an Aura Energy Generator. If too many aliens infest a zone, then the AEG goes puff and you've failed. Fail three times, and you might as well have stuck to the picnic circuit...

To get between zones, you have to shoot one of the dragon aliens. These are but one of several types of enemy: some travel alone, some in formation and some disguised as dragons. Cunning, eh? There are also motherships, which take a few shots to dispose of.

When you've shot the dragons (clue - like Defender, the smartbombs are best saved for the biggest and hairiest of the aliens), there appear icons depicting various prizes, like more power, more time, more bombs or exit to another level.

Aliens left alone in one area tend to go berserk. No respecter of the Country Code is Joe Alien. You are therefore advised to share your time equally between all ten zones in a region.

If you succeed in completely clearing a zone, it will seal off and you can concentrate on the rest. Clear ten zones and you can switch to the next region.

On the flip side of the cassette comes Molecule Man, a standard wander, bump, die maze game in three dimensions. And a free maze designer. It's been reviewed before, but I wouldn't bother looking it up...

The "MadX" range aims to offer something extra in the form of a previously released game on the B side. Unfortunately, this means you get two duff games.

Energy Warrior is the type of game which went out of fashion when vertical scrolling was discovered, and I can't see any reason why it should be allowed to creep back into vogue.

Simple shoot-'em-ups are often the best, but they need to present a challenge you want to take on. Energy Warrior is just dull, lacking the traditional three lives with a bonus every 10,000, lacking a variety of things to shoot.

And the fact that the thing you do want to shoot spends too much time off the edge of the screen makes this frustrating to play.

Energy Warrior is Defender without the radar, or the men to defend. Landscape scrolls below, fast (and I mean fast) nasties swoop and swirl, you go bammabammabamma.

There's little in the way of plot or frills to enliven the whole procedure. It's one of the more difficult shoot-'em-ups I've played, but there isn't enough going on to really retain my interest.

The various sound effects are confusing, and it's difficult to chart your progress.

And the game follows the unfortunate trend of titchy playing areas, so I really can't see much in it. But it is fast...