At its heart, Earthlight is a sideways scrolling shoot ’em up with some impressive graphical touches for the Sinclair Spectrum.
Keep an eye on your fuel and shield levels as you fly through each level, trying to collect small boxes called matter transmitters. Once you've collected all of the transmitters, return to where you started to complete the zone.
You can choose which zone to try next, but you must complete all of them to finish the game.
Robots will try their best to stop you in each zone, so use your missiles to destroy them as you weave in and out. You can also adjust the balance between fuel, missiles and shields when you enter a new zone.