If you didn't have the full coin-op arcade machine in your home, this was the best way to play R-Type in the late 80s, if you wanted a more faithful rendition than what the PC-Engine / TurboGrafx-16 could offer:
R-Type on the Sharp X68000
It blew away all other home computers versions, including MSX, ZX Spectrum, Amstrad CPC, Commodore 64, Atari ST and Amiga!