Star Avenger

From the web site of one of the authors, Steve Wallis (http://www.socialiststeve.me.uk/games.htm):

If you navigate your spaceship above and inside an alien landscape, shooting at will (subject to the limitation that you can only fire four missiles at a time) then do not be too surprised that the aliens want you dead! The name of the game implies that those same aliens have done somthing terrible to the Earth that needs avenging, but I am of the opinion that all alien races that have achieved interstellar travel are good beings and that conspiracy theories about alien abductions are made up to justify beliefs that our world leaders should be trusted rather than loathed for the wars they start and poverty they inflict on ordinary people across the planet. Have no fear, mere mortals will not have too much success on avenging whatever these aliens are supposed to have done, since even level 1 (supposed to be easy) is fiendishly difficult with missiles often aiming at you! This is the only one of our games that we had previously implemented on Sharp platforms. It was primarily written by Sean in BASIC, like all our computer games, but I wrote the compiler from BASIC to Z-80 machine code (understood by the Amstrad and now the emulator) as well as implementing bits of code requiring particularly efficient implementation (specifically those involving graphic operations) in Z-80 assembly language.