First, you need Turbo C++ 3.1 

You can easily find this IDE when you google it.  

After this, go to the directory 'solomonc' and edit the COMPILE.BAT file so that it points to the directory of Turbo C:

<TURBO_C PATH>\BIN\TCC -1 -I<TURBO_C PATH>\INCLUDE -L<TURBO_C PATH>\LIB -eSOLOMKEY.EXE SOLOMKEY.C SOLFUNCS.C VGA.C

For example:
I have put TC directly on C: (so, there is a root directory C:\TC in my Windows PC)  and the above record is:

C:\TC\BIN\TCC -1 -IC:\TC\INCLUDE -LC:\TC\LIB -eSOLOMKEY.EXE SOLOMKEY.C  SOLFUNCS.C VGA.C

Then hit COMPILE.BAT and replace the exe file of the game with the new one. 
It is better to run the COMPILE.BAT from a command line window so that you can see possible errors/warning of the compiler/linker in case you decice to play with the source.

So ...if you see in the source files comments in greek, don't give up. 
There are a lot of free translators in the web.

