An attractive, smooth-running arcade three-parter that's simple enough to lure you inwards yet complex enough to give you a run for your money after a level or six (which frankly is all I've ever managed). You grapple first with what appear to be a mutant bunch of those tried and true Invaders, the spear-carriers of the video game and here, appropriately enough, dubbed "Walkons".
This task is complicated by the gradual release of hazardous and disconcerting bouncing bombs. Proceed to the cunning bonus stage which entails some tricky manoeuvring of a "Henk Class Cruiser" before destroying some small and perfectly defenceless white dots. Finally you must pilot another ship through rows of enemy craft and past lethal comets in order to dispose of a hostile spy satellite.
Thereafter it all repeats, but with more Walkons, bouncing bombs, enemy craft, comets, spy satellites and, of course, small, defenceless white dots.
Controls are pleasingly simple, graphics neat if a trifle flat and unimaginative. A game where calm and method count for more than flash and bravado which at first made me think its pleasures were subtle, but left me wondering whether they were merely shallow.