when it reviewed Zarch with a score of 979, the highest rating ACE had given at that time, only bettered by the later Atari ST port Virus at 981.

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, but there is comparatively less land and more water, making complete infection more likely.

[2] Controls are extremely sensitive; simply moving the mouse while taking off can cause the lander to explode on the launchpad.

The lander expends fuel and must occasionally return to the launchpad to refuel, with successful landings being difficult.

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.

In advanced levels a high-altitude, fast-moving bomber craft appears, dropping packets of virus particles in profusion.

This craft is difficult to destroy, since the angle needed for the lander to match its speed is such that the cannon cannot easily be brought to bear.

Although the graphical environment, controls and handling of the lander were similar to the released version of the game, neither enemies nor virus were present on the landscape.

While the lander was stationary on the launchpad, moving the mouse (which would normally tilt the attitude of the craft) would cause it to immediately explode.

The landscape routine uses fixed tile sizes, meaning that the depth of view (amount of terrain being rendered) directly influences the frame rate.

The higher resolution Mode 15 was not used because that leaves less available memory and the required VIDC bandwidth also slows down the processor.

Shadows of the lander and enemies are projected vertically onto the ground, which does not cater for landscape curvature but is fast.

Four major routines are used in the game's programming: The hillside landscape is generated from a number of pseudorandom sequence sine waves.

[citation needed] The Amiga game Zeewolf (1994) and its sequel have a noticeably similar design and appearance to Zarch.