Shilpheed it's a great vertical shooter which was originally make to the PC88 japanese computer, then ported to PC. Years later a remake was done to MegaCD, and a sequel for PS2 on 2000.
Snatcher it's an excellent conversational adventure game by Hideo Kojima, the man behing the Metal Gear series, Zone of the Enders, etc. Was originally make to MSX, later remaked to MegaCD, which it's the only one oficially released outside Japan (The MSX version was unnoficially translated though). Also ports were made to PSX and Saturn, but never left out Japan.