The combat of Hegemony is centered around the campaign of armies, just like it should be. In Total War, war was decided by a single or a series of battle, and end in a decisive victory or defeat, and more times than not, a complete annexation of territory. In Hegemony, wars rarely end, and instead are based around raiding parties and the capturing of outposts, which was how the Ancient Greeks fought (the Peloponessian war lasted 27 years, neither side launching direct attacks against the opposing city, instead raiding the outskirts and capturing distant allies, with the exception of a botched attemp to capture the Pireaus.) Combat in Hegemony is decided on how well your league produces food to feed the armies, the transportation of your armies, and the wages which fund the hoplites. Of course, battlefield tactics will determine the outcome as much as the upkeep of troops.
One of the very few cons of this game. Diplomacy is limited to only ceasefire and alliances. The lack of a complex diplomacy system is justified by the developers because Phillip rarely used diplomacy to conquer lands. This is certainly not true for the Greeks, who exchanged hostages, set up defensive alliances, client states, arranged for population of entire cities to migrate elsewhere (The Athenians evacuated their city during the Xerxes' invasion).
This game is pretty difficult.
-Historical stuff and the Greek feel-
When speaking of this game, I always mention that no other game has resembled the independant Greek city state as well as this game. Perhaps, that is the case because no other game has attempted to do so. The factions in this game are seperated into different leagues, which are represented fairly well historically.