Gyron, a game in which brains and logic count, stands in a class of its own.

Maze games are usually easily described - but not this one. Firebird's Gyron is a complex game comprised of two labyrinths, one nestling in the other. Atrium is the easier game and within it is Necropolis with the wisdom of the Sorceror hidden at its centre. The idea is to reach the founts of wisdom before the sorceror can rise form the dead to claim his knowledge.

Massive balls roll in predetermined, circuitous paths through the trenches of the labyrinths. Contact with those means instant death. Rising above the walls are monolithic towers guarding the paths to Necropolis and wisdom. Each tower faces one of the four points of the compass, blocking certain routes, and each is ready to strike if you come within range.

The screen is viewed through the cockpit of your hedroid craft in full 3D glory. Two green lateral indicators to either side of the screen act as laser canons. As you have only a forward view of the screen, red bands descend to indicate side entrances.

A green square at the bottom of the screen indicates your position in the trench. Colliding into walls will dam- age the hedroid and an indicator in the control panel shows how much damage you have sustained.

A timer is linked to the central computer and is synchronised to the motion of the balls. Below that is a revolving icosahedron which changes to one of 12 colours related to each section of the maze.

The graphics are wireframe with the balls and towers in solid blue. The balls are masked if they are rolling behind a wall. Movement is fast and smooth, and a pat on the back must go to the four programmers who took over a year to produce the game.

Firebird has produced a brilliant game combining strategy and arcade skills. A Porsche 924 motor car is on offer to the first person to discover the secrets of Necropolis.

If that isn't an incentive to buy this game, I don't know what is.