This is a cool project, but the author should note that they _are_ likely creating a derivative version of Civ1 here. It might look somewhat different, but that's clearly just 16-bit (?) intel opcodes in a slightly spicier form.

It's very unlikely this sort of approach will end up with a copyright-free codebase, though it might be useful as a source for a cleanroom approach. The author shouldn't be discouraged -- lots of other recompilation efforts work this was as well, but it's a muddy place to be.