Nice idea for a game! Have been thinking of making a similar one for many years, but with you it did not end only with thinking :-) Do you think you could give me a little help with getting back to DOS programming as you seem to prefer plain mode 13 like me? Can I contact you somehow?
Thanks for you kind words.
I first learned programming in Turbo/Power Basic for DOS. `SCREEN 13` was what I knew how to do, so it made sense to me to try using it again. ^_^ I made this game in a few weeks (Jan. 2017), and before that it had been many year since I did anything in DOS, and I have not done anything since. My process is 100% not ideal, but I can walk you through the environment I set up. I'm assuming you found the source code, but my build scripts are not in there. At first I was happy using Turbo C 2.01, for nostalgia. After a while it got to me though, and I had to switch to Sublime Text (my preferred editor), I kept using Turbo C as the compiler though, this gist should give you everything you need for that (the bottom of 'dosbox-0.74.conf.txt' has the code to invoke the compiler, and run the game from in DOS).
Turbo C 2.01 is not ANSI compliant, and only runs in DOS; if I were to start over I seriously look at using DJGPP (a port of GCC to compile DOS executable).
Thank you again for you interest, and I hope you end up making something! If you have any more questions my email is: hitch@hitchh1k3rsguide.com I probably cannot be too much help though, since the project was so short, and a while ago. ^_^