a shoot-'em-up mode in which alien vessels were seeded in the fields, feeding on the crops and growing until they could become airborne, at which point they headed for the town. The player could destroy the aliens on the ground as they fed, or (for reduced points) tackle them in the air (the aliens were agile but could not return fire). If an alien reached the town, the game was lost. A minor bug permitted the plane to be landed upside down without consequence, so long as the landing gear had been deployed. Although better known for his Formula One simulation games on the PC and Amiga platforms, his first motor racing simulator was Revs, a Formula Three simulator that debuted on the BBC Micro platform in 1984. The BBC version of Revs featured just one track, the Silverstone circuit, but the realistic implementation of motor racing physics and artificial intelligence of the computer controlled components gave the game enormous depth and replayability. An enhanced edition of the BBC version was later released, in 1985, called 'Revs 4 Tracks' which included Brands Hatch, Donington Park, Oulton Park and Snetterton race tracks. A Commodore 64 version of the game, entitled Revs Plus, was released in 1986, which added the Brands Hatch track to the game. Later the Commodore 64 version added the Nürburgring to this list to continue the "4 Tracks" theme as Brands Hatch had already been included with the initial REVS Plus release. The Nürburgring was chosen as its new layout had recently been completed and computer based design data was available. This gives an idea of just how accurate REVS was as a simulation rather than 'just' a game. The Sentinel was published by Firebird on the BBC Micro in 1986. It was a 3D puzzle game, featuring ten thousand levels, in which the player had to manoeuvre his way through a landscape of cliffs, trees and boulders to topple the ominous Sentinel. The game was a critical and commercial success. Conversions for the ZX Spectrum, C64, Amiga, Amstrad CPC, Atari ST and PC soon followed. A sequel, Sentinel Returns, was published by Psygnosis in 1998 on the PC and PlayStation platforms. Crammond's attention returned to motor racing simulators. Stunt Car Racer was a slightly offbeat driving simulation, rewarding the player for performing outrageous stunts on a number of elevated, roller-coaster-like courses. Although less serious in tone than