How do you feel about fractals? Lucasfilm Games really likes the little devils - so much so that it's based a series of programs around them!
What a fractal does, according to my mathematical mate, Phil (Phractal) South, is create a 2.5 dimensional real surface via random numbers and... no, I didn't understand it either, but it's obviously awfully clever.
What matters more to you, the end user, is what Lucasfilm Games has done with its fractals. It's built a planet out of these formulae, and called it Fractalus - and you can steer your Valkyrie fighter around a real world and rescue stranded victims of the Earthling vs Jaggi War, big match of the 21st century.
This all appeared on the obnoxious Commodore originally, of course, and looked mighty convincing too. However, while the Spectrum can do many things far better than the American OAP, it must be admitted that its graphics leave something to be desired... and rather a lot of something at times like these. All that lovely landscape looks more like a fly-specked graph than an alien planet.
If you can get used to the fact that for all the flashy mathematics, the surface still looks very flat, there's a half decent game in here. After your automatic launch from the mothership you scout around the surface searching for your comrades, who wait patiently by their wrecked craft.
Find one on the long range radar, then close in, touchdown and wait while he runs up and you hear his knock at the door before you open the airlock. Pausing only to wipe his feet, he'll then step inside and it's on with the shields once more and off in search of another survivor, until you've reached your mission quota.
At any time after that you can return to mother and set off on another mission, this time with a higher quota and worse risks. For starters there are mountain-top gun turrets that fire at you, then on later levels flying saucers swoop down. There's even night flying and the odd nasty surprise when the approaching astronaut isn't all that he seems.
Flying a Valkyrie is a skilled job, and there's the standard collection of indicators and radar panels to keep your eyes darting all over the screen. At least those kindly Lucasfilm people have thoughtfully included a training mode in which you don't get used for Jaggi target practice.
A different angle on shoot 'em ups then, but bugged by the Spectral graphics, which make it look like you're flying through a page of Teletext.
What lies behind the next ridge? A fractal landscape means that there's actually a location behind the rocks, even if the flat graphics don't suggest as much.
This is the action area, with the targetting scope, though you also get crosshair sights on the main screen, and a Blackpool lights display to warn you that the enemy's locked on.
An indication that the computer is taken in by the solid surface, even if you aren't. The altimeter shows varying ground level and your height above it.
Messages reminding you to shut the door before you blast off, or to switch off your system so that a pilot can approach, appear here.
If you don't want to give a V sign to your lovely V wings, keep an eye on these lateral clearance bars.
When the energy gets low on here you'd better call home for your mother(ship) to come collect you.
Picking up people is lots of fun - especially when you use the radar here and log up another rescue, shown in the panel to the right.
More thrust, Scotty... and more height! These two indicate engine power and closeness to terra fractal.