Mr. Mephisto was a video game originally developed

Video game developer

A video game developer is a software developer that creates video games. A developer may specialize in a certain video game console, such as Nintendo's Wii, Microsoft's Xbox 360, Sony's PlayStation 3, or may develop for a variety of systems, including personal computers.Most developers also...

 and published

Video game publisher

A video game publisher is a company that publishes video games that they have either developed internally or have had developed by a video game developer....

 for the Commodore 64

Commodore 64

The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...

 (C64) by Euro-byte. The C64 version was written by Dave Lucas with graphics by Graham Hunt.

Summary

The game consisted of a number of levels through which the player had to navigate to collect rings and then make it safely to an exit. A team of demons attempted to block the player's path. Contact with a demon resulted in instant death, and one or more scrolling staircases further hampered the player's progress.

Following success in the C64 market, Euro-byte commissioned a port of the game to the BBC Micro

BBC Micro

The BBC Microcomputer System, or BBC Micro, was a series of microcomputers and associated peripherals designed and built by Acorn Computers for the BBC Computer Literacy Project, operated by the British Broadcasting Corporation...

. However, no source code was available as the game had been coded in 6502

MOS Technology 6502

The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...

 assembler directly into the C64's monitor program. The code was re-written from scratch. Eurobyte subsequently commissioned a version for the Acorn Electron

Acorn Electron

The Acorn Electron is a budget version of the BBC Micro educational/home computer made by Acorn Computers Ltd. It has 32 kilobytes of RAM, and its ROM includes BBC BASIC along with its operating system....

, but this was never released.