You are the commander of a squadron of three fast and highly manoeuvrable space attack craft, ordered to raid an alien base on the Moon. The aliens, understandably miffed at this, set up a series of defensive zones, each more difficult than before, which you must negotiate.

The first three screens depict hilly landscapes, thickly populated by radar stations, anti-aircraft batteries and missile silos. Also dotted about are enemy tankers - vital to your mission, for by hitting them with your bombs you gain a much needed boost to your fuel reserves. This is necessary to enable you to reach your own tanker, which is sited between stages.

Beware of the space mines that surround your tanker - these aliens don't miss a trick. Stages two and three have flying bombs and fireballs just to keep things interesting.

Stage four takes you over the highlands, sown with missiles and not an enemy in sight until the very end. If you miss this, it's curtains!

Refuel once more and you're through to the final obstacle - a long winding cavern with sharp bends and vertical shafts. No problem with fuel here, because flocks of enemy tankers block your path. Having said that, none but the very skilled will make it through the cavern. The enemy base lies tantalisingly beyond, though some may never see it.

Good graphics, a limitless supply of laser bolts, bombs and poachable fuel make this a satisfying and compulsive game. Skilful use of the faster/slower key makes evasive action easier. Use of this key while refuelling means that you can take on more fuel and its use is vital while flying through the caverns.

One of the nice features of the program is you can skip stages by selecting games one to five and set the difficulty by selecting A to D.

A good value game, crammed with action and needing skill to test the most ardent arcade fanatic. A recommended version of the old classic.