Caesar
4 is a really good game
This
game's is not easy, it requires a lot of thought to plan out your city
but there is a good learning curve and there is always a choice between
two missions (one usually having military objectives and one
economic/cultural ones). Once you get the hang of how the mechanics of
the game work it is very rewarding building your city up to meet the
objectives. I played through the game twice just so I could do all the
missions I missed the first time.
. If
you are looking for a combat oriented game then this is not for you, as
the combat system is more of an afterthought (an easy way to get round
this is to build lots of walls and towers to defend the city).
Overall
this is the best city building game I have played, including Caesar 3
(ok, I haven't played it since I was a kid so can't properly compare).