Another thing is you don't need transports/ships to carry troops across the sea, once you get the required technology, you can just move them in the water, and they just hop on boats, but land unit convoys are vulnerable to sea vessels and can be instant killed if they catch you in the water. They basically flipped the whole combat system upside down, and I prefer the other systems better. A few minor things I didn't like about the combat strategy, cities being able to defend and attack back without having any units defending.
Just bought this game yesterday, anyone else got it? Only thing I didn't like was you had to use Steam, but there is already a patch out that lets you play without even installing steam.
