Then might I suggest reading through the source code to some of the classic games of the early 80s like Zork, Star Wars, Centipede, Dig Dug, and Hitchhiker's Guide to the Galaxy.

https://github.com/historicalsource

Some are written in ZIL (Zork Implementation Language) but most are assembly, so a little experience is necessary to make the most of them. The brave ones amongst you might even manage to build the code into working binaries - good luck!

For those wanting something written in a more current language, and consider C++ to be such a thing, then newer titles like Jedi Academy for the XBox are also there.