The last tool we need for now is something to disassemble the three binaries in the game. My 2010-ish attempts used a... let's keep it at "not exactly legit" copy of IDA Pro and Hex-Rays. This time, I'm gonna go the legit way and use NSA's Ghidra - no need to fear about malicious cracks or being unable to share files, but I'll have to deal with having to implement a Borland C++ de-mangler and all of Borland's structures by hand instead. Ah well, we will be dealing with this one later, and for what it's worth IDA's support for Borland was already a fair bit lacking even back then.
Go to Ghidra's Releases page on GitHub and download the latest release (10.0.0.1 at the time of writing)
Extract it to some location on your system (on a Mac, I used /opt/ghidra)
Create a symlink so it ends up on your PATH: sudo ln -s /opt/ghidra/ghidraRun /usr/local/bin/ghidraRun
Start it by running ghidraRun in a Terminal.
TODO: Once figuring out how to integrate Eclipse into Ghidra so that tests work, describe that here
If you have ~25€ spare and are new to working with Ghidra, go grab a copy of "The Ghidra Book" at Amazon.