Interesting, thanks. By this point, I'll bet there's a page somewhere with the codes...in fact, the copy that I downloaded has a file "PROTCODE.TXT" with the co

Interesting, thanks. By this point, I'll bet there's a page somewhere with the codes...in fact, the copy that I downloaded has a file "PROTCODE.TXT" with the codes to look up. They look like they're just 16-bit values. It tells you to look up things like "A, 5". In the table, there are 16 letters (columns) and 128 numbers (rows). I'll bet it's just checked against some algorithm in the game code. It's tough to see where some of the code comes from, though. The game copies chunks of the binary around within itself, and constructs function calls "by hand" (pushing a memory address byte-by-byte, then "returning" to it). It's not horrendous to trace, but more than a half-hour job for me.