No one mentioned this, but the SNES game IS based on the Shadowrun role playing game. So is the newer Shadowrun game for the XBox 360 and PC. The newer one needed some work in my opinion.
There is also a Sega Genesis version, much better than the SNES one in my opinion. Never played the original P&P myself, was always more into non-fantasy(as in no elves, orcs and magic) cyberpunk.