Do not believe those who say this game is too difficult
I recommend getting this game if you've played Caesar 3 or Pharaoh before, and have experienced their challenges, and have enjoyed them. Not everyone has the taste or the skill to play this genre.
Caesar 4 improves on many elements of its predecessors, such as the fictitious 'walker' concept, which fixes an upper limit to the size of your city. At the same time, some concepts, such as the micro-placement of roads can be annoying. At the same time, the game hogs an excessive amount of resources as the city becomes immensely large. The gameplay also tends to become pretty similar in progressive levels.
Caesar 4 is easier than Pharaoh, and much easier than Caesar 3, at least on the Normal difficulty level, so I've rated it accordingly. The early stage of the game requires the most skill and attention. In one strategy, you can pause the game and build your whole city in the beginning. If your design is good, then all you have to do is fast forward the game, and supervise, mothballing industries, adding colonies etc. as and when the time comes. Since this strategy works for nearly all the maps on a normal difficulty setting, it takes the fizz out of the challenge of city developing offered by its predecessors. Admittedly, I haven't replayed the game on a higher difficulty setting, due to the similarity of gameplay in all the levels.
I don't know what gamespot had against this game, it gave it a 6 for sound. The score of the game is light, varies with the size of your city, and is appropriate for a city builder set in the Roman era.
I for one quite enjoyed Caesar 4. Again, if you're thinking of getting this game, try playing Caesar 3 or Pharaoh first.