This is the second time on HN this week I've seen someone reference Stars! It was such a fun game to play back in the 90s. I've had a similar desire to have Codex decompile a pet 90s game of mine for further modification. Not sure how far one could get before Codex complains about reverse engineering software.

EDIT: Here's the other Stars! thread. https://news.ycombinator.com/item?id=49755378