Norbert Kehrer wrote an emulator/conversion, of the classic arcade game Phoenix from 1980 for the Amstrad CPC. The original arcade machine was made by the American company Amstar and had a 8085 CPU. So, the Amstrad CPC can directly run the original game program on its 8085-compatible Z80 CPU. In order to emulate the arcade machine's video and sound hardware on the Amstrad home computer, he wrote specific Z80 routines for that. These are still a little bit buggy now, and the sound is still bad.
He made two versions of the game. One with sixteen colors but lower resolution (file "phoenix"), and a second one with the original resolution but with only four colors (file "phoenixh").
You can download a disk image with both versions of the game from Norbert Kehrer's homepage.