I played it quite a bit back then and didn't find anything else, so I doubt there's much more to it. It's a shame they didn't do a fuller version for the 2MB Amigas (I know - Sim City 2000, but that's a different story).
The SNES had a great version of the original Sim City which had background music, special buildings and more stuff like that. Should've been easy to do on an A1200...
