One of my favorite game, probably the only RTS who used the terrain like that, you can make ambushes everywhere: forrest, wheat fields, hills ... The campaign is hard, long and tactical, with epic sieges: you'll have to defend your garnison from barbarics tribes who'll come at you with ladders, rams, siege tower. Considering the game only allow you to play 3 Factions (Romans, Gauls, Egyptians) i suggest you to install the Imperial mod that add Greeks, Carthagenes, Persians.