The game was published as a type-in in issue 11 of Computer and Video Games magazine, September 1982, pp.36-39; the listing gives the date of creation as June 1981.
Various already typed-in versions of the TRS-80 game are circulating on the internet. The one attributed to "P. Knott" is known to contain errors.
The ZX Spectrum version in the archives is credited to Martin Malley and is presumed to be an unofficial port. It is extremely buggy, and potentially unplayable. For example, to even read the instructions you need to BREAK into the program and type GO TO 131.
There is an unofficial C64 conversion, by Barry Hart, dating from 2017.
At some point the original game appears to have been translated into Dutch for C64 and/or Vic-20.
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