Zarch (also known under its ported name of Virus) is a computer game developed by David Braben (better known as the co-author of Elite) in 1987, for the release of the Acorn Archimedes computer. Zarch started off as a demo called Lander which was bundled with almost all releases of the Acorn Archimedes.
In 1988, Zarch was ported (under the new name, Virus) to the Atari ST, Amiga (coded by David Braben), and IBM PC (coded by Chris Sawyer). It was later ported to the ZX Spectrum by Steven Dunn.
The game was groundbreaking for the time, featuring a three-dimensional mouse-controlled craft (the "lander") flying over a tile-rendered landscape that dazzled reviewers in a primarily 2D-dominated game industry - ACE (Advanced Computer Entertainment) magazine led with the headline "SOLID 3D - the future of games?" when it reviewed Zarch with a score of 979, the highest rating ACE had given at that time, only bettered by the later Amiga port Virus at 981.
Virus was one of the first solid 3D games and was also the first to have 3D lighting effects and shadowing, although these are less sophisticated than those of Zarch.
Plot
The plot of the game is reminiscent of the arcade game Defender, in that the player, piloting a lone craft with limited firepower, must defend a finite landscape against ever increasing waves of enemy craft. In Zarch, the landscape is being invaded by aliens who are spreading a virus across the landscape. The Seeder vessels are slow-moving, predictable, and easily destroyed, but as the game progresses they are supported by increasing numbers of flying support craft, which do not scatter said virus but instead attack the player.
The Seeder vessels scatter red virus particles across the landscape. As they land, they turn the green landscape to brown and red, and cause the trees to mutate. Some flying enemies shoot the mutated trees, to cause themselves to become much more aggressive and dangerous. To clear each attack wave, the player must destroy all enemy vessels.
At the conclusion of each attack wave the player is awarded bonus points for the amount of landscape which remains uninfected. After four attack waves have been successfully repelled, the player is awarded a new landscape; however, there is comparatively less land and more water, making complete infection more likely.
Gameplay
Zarch is a notoriously difficult game for beginners. Controls are extremely sensitive; simply moving the mouse while taking off can cause the lander to explode on the launchpad.
The lander has a single thruster pointing directly downwards beneath it. Firing the thruster causes the lander to fly straight upwards. The lander has a flight ceiling above which the thruster will not fire. To fly in any direction requires the lander to be tilted in that direction. The lander can only pitch and yaw; it cannot roll. Too much tilt can cause the lander to turn upside-down, a position which may be difficult to recover, and can cause the player to crash the lander by accidentally thrusting downwards. The lander, although agile, is vulnerable, and may be destroyed by a single enemy shot.
The lander expends fuel and must occasionally return to the launchpad to refuel, with successful landings being difficult. The lander must be completely level to land. While refueling, it is vulnerable to attack from the air.
Every round fired costs one point, and the lander is equipped with a rapid-fire autocannon. This makes it possible to achieve a negative final score if one does not actually hit anything. At such times the game wryly points out that slugs and dried up bits of lichen have been known to get better scores than that.
No powerups are available in the game, although the player has a limited number of smart missiles, and smart bombs and is awarded a new one of each with each extra life. Some enemy craft are so agile as to be able to outmanoeuvre the missiles, and the smart bombs have a very limited range.
Radar screen
In the top left of the screen is displayed a "radar screen", which provides a map of the whole landscape, with the position of the lander and enemy craft marked on it. Uninfected territory appears green; infected territory appears red. The radar detection is provided by rotating scanning-towers which are evenly spaced across the landscape; accidental destruction of these results in loss of detection in that area, and black squares appear on the map.