System 15000 is a 1984 video game by A.V.S. It was originally conceived, designed, and programmed by Lee Kristofferson (born John Wagstaff) in assembly language for the Commodore 64. Versions were later ported to the ZX Spectrum and BBC Micro, both written in BASIC. This was the first game to simulate computer hacking.
A sequel was planned by Lee Kristofferson but never released.