Basically, Village phase is the phase where you try to build up your economy (so also try to slow down the economy of your enemy). Town phase is where you build your empire (claiming new pieces of unclaimed land, and fight for the pieces of unclaimed land). And City phase is where you try to concur already claimed land from your enemy. So yes, you're not supposed to attack buildings with simple soldiers. You're just supposed to slow down your enemy at that point (go around his towers, attack his economy). Once you get to city phase, you can make siege engines, and then you're supposed to try to gain territory from him. Of course, we're still trying to work out a nice balance for all this (how long each phase should take, and how easy or hard it should be to break this typical pattern by attacking earlier). But this is about the general idea. When you really need to get down a tower in phase II, well then you're a bad player, as your opponent shouldn't have been able to make a tower there in the first place. Towers also have a big disadvantage: when you go around them, they don't come chasing you, as opposed to an army.