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[vdub_bobby]

The article is really great, lots of details about how he got around hardware/OS changes, reverse engineered data compression, and more. Well worth a read.

http://sol.gfxile.net/dr_gdm.html
Here's an excerpt:

Quote

Trying to find another easy way out, I compared the characteristics of the code with known compression algorithms, discarding most of them due to the requirement of overly large lookup tables or code complexity. The source code to Info-ZIP is invaluable for these kinds of things, as it implements most common compression algorithms, not only the ones found in modern ZIP formats. In the end, it was clear this was a proprietary algorithm, so I really did have to dive in.

I spent a couple days poring over the code and trying to re-implement what it does in C. Once I understood what the assembly code was doing, I took another glance at the section that decompresses the cutscenes and realized it's almost the same - except for some additional encryption. I made a variant of that code and the data problems went away.

At the end of the article there's a link to where you can download the ported Windows version, released as freeware.

[bfutrel]

I remember playing the demo of the DOS version many years ago. I heard that it was released as freeware for Windows and played it. It's a great game, but apparently my temper is very short with this game and I smashed the keyboard tray.....

It's too easy to get stuck at higher levels.