You live on the planet Sangfalmadore and, being an ambitious sort of chap, have entered the Sphere Training Corps. The most fearsome pa,t of the STC is the Sangfalmadore Run, made even more deadly by a recent earthquake trapping Colonel Matt Ridley. You’ve volunteered to rescue him, but only complete mastery of your fighter sphere will see you through.

The Run is made up of eight levels, each subdivided into four interconnected isometric mazes. There’s much more to the game though, than simply having a good enough sense of direction to find the exits and lifts. The sphere is incredible not only because it can shrink, but also because it can expand and change its weight by touching special tiles. Being small allows you to go through narrow passageways, being light means you don’t fall through cracked tiles, but at other times you need to be big and heavy to push objects around.

There are also hostile tiles which can trap you, domes which can send you zooming off at high speed, and assassin generators. Assassins are hostile drones which take a life on contact — unless you have a shield (gained by touching the relevant tile) or shoot them first. You only have a limited amount of ammunition, but you can get a refill by bumping into an ammo dump — four of these are placed by the player before the start of the game. The Run’s toughest problem however, is the rapid decay of all the blank tiles. Contact with a decayed tile is deadly, so there’s a time limit.

Clearly ISS is a fairly complex game, made even more so by the ball’s inertia leading to control problems. Persistence has its own reward though, and a game of immense playability is soon revealed. Both skill and strategy are needed to get through the levels and this combination gives the game long-lasting appeal — it really grows on you the more you play it.

PHIL ... 90%

Producer: Electric Dreams
Small change: £9.99 cass
Author: Four's Field