Exolon is a run and gun game programmed by Raffaele Cecco and published by Hewson in 1987 for the Sinclair ZX Spectrum, Commodore 64 and Amstrad CPC 8-bit computers. It was later converted to Enterprise 128 and to the 16-bit Amiga and Atari ST platforms.
The player takes control of a futuristic soldier across several flick-screen levels of gameplay. The screens that make up these levels are filled with various generic aliens as well as gun-emplacements, homing-missiles, land-mines and other hazards. The player can defend themselves with both a gun and rocket-propelled grenades. The two different weapons are effective against different enemies.
The enemies themselves are very varied taking the form of flying aliens of the type traditionally found in shoot 'em ups as well as homing missiles, fixed guns, tanks, land mines, swarming red pods and "crushers" which shoot out of the ground.
Part-way through each level, there is a pod in which the player can "upgrade" until the end of the current level to an armoured exoskeleton with improved weapons and armour. Attempting to finish the level without this upgrade results in a score bonus.
Source: Wikipedia, "Exolon", available under the CC-BY-SA License.