Earthlight is a computer game published for the ZX Spectrum in 1988 by Firebird Software. It was written by Pete Cooke.
The player takes the role of an alien explorer from the star-system of Arcturus, called Slaatn, who has been drawn off-course by a beam of energy from Earth and has had to make a landing on the moon. Slaatn must neutralise the box-like transmitters and thus eliminate the force field.
Earthlight is a shooter featuring parallax scrolling and shadow effects, a novelty for the Spectrum.
CRASH awarded the game 90%, with the reviewers impressed with every aspect of the game, particularly the 3D shaded graphics and the sound effects. The gameplay was compared to that of Uridium. Your Sinclair awarded 8/10, describing it as a polished game but without the depth of Pete Cooke's previous releases.
Source: Wikipedia, "Earthlight (computer game)", available under the CC-BY-SA License.