Can the original code simulate the stock market as it operates today? The main reason I would want to convert the engine to a modern language is to make it easy enough to understand that I could add features.

I think it will definitely need refactored in order to do an overhaul like that.

But the best way I can answer your question. WSR does not claim to simulate real markets. It probably leans too much into fundamentals for our time, at least for the blue chip stocks in the game. What is actually is is a M&A and tax evasion simulator on top of a financial market sandbox to create tax implications to be avoided.