There is the goal of having a high population. I got to the really hard goal of Megalopolis.
You have to put up with a high crime rate. A city that isn't very pretty. You need to wriggle the tax rate back and forth. But it can be done.
I really lost interest in the game after that achievement. SC2k is much better because you design something.
I never won any of the dullsville scenarios (SC and SC2k). Give that one a try and let us know how you did it.