Digital Prawn writes:-
This is the HiSoft BASIC compiled version of the sudoku CGC entry game that Gavin sent me. It wasn't intended as an entry to the compo in itself, but I included it in the download zipfile so people can try it out. It runs much faster than the original interpreted version. For example the puzzle I ran on the interpreted version took something like 2 hours to solve, but only 9 minutes on the compiled version. For the sudoku programs, I use and strongly recommend the old JPP emulator for DOS, which I run natively under Windows XP. It is a very fast emulator, although lacking in many features by modern standards. It is downloadable from http://www.worldofspectrum.org/emulators.html at the time of writing.

Gavin's Email to me states:-

I didn’t bother with a loader or anything, so the .TAP file contains just the compiled code. So, LOAD””CODE 58178 and then call it.
 
It’s not quite the same as the original I sent though. The iteration update routine is not run for every value, and also a known issue with the compiler causes the iterations counter to have yellow paper when it is back-tracking. This is a bug, but one I like so I decided not to fix it!