Caesar II leaves the wanted board
A clean-room decompilation of Caesar II, byte-exact against the original executable, plus a native and browser port built on it - the first of the two undocumented earlier titles to get an open engine, found through a community post rather than a search of this site's own making.
Caesar and Caesar II have carried the same line since this site's first research pass: no engine, no format documentation, virgin reverse-engineering territory. That stopped being true for one of them. The second-impressions project's Caesar II Reconstruction recovers the 1995 executable as C source and rebuilds it byte-for-byte against the original PS.EXE - not an approximation of the game's behaviour but the literal machine code, reproduced. A companion repository, the Caesar II Port, continues that recovered source onto SDL3: the DOS-and-Windows calls are replaced one function at a time, the game's own logic is left untouched, and the result runs natively on Windows, Linux and macOS, and in a browser over WebAssembly, loading the original's save files directly.
Both are now listed as engine projects on the Caesar II hub, and its wanted callout is gone - the first time that has happened for either of the series' two undocumented titles.