In Galactic Civilizations all ships had an attack and defense value. You could stack ships together but that really meant nothing in terms of combat. And you picked ready made ships.

In Galactic Civilizations II, attack and defense has much more depth. All ships will have 3 types of attacks - beam wapons, mass drivers, and missile weapons. And 3 types of defense: Shields, armor, and point defense.

You also build classes of ships rather than pre-made ships. So you take your technology and design your own unique ships both in how they look and what they do.  The more complex the ship, the more logistical support (logistic points) it uses.

Based on your logistics ability, you will be able to put together ships into fleets which will act together in combat where each ship gets to take a shot during the player's attack role.

So you might create a ship called the DoomGiver class. Attack: 9/3/5 and Defense: 5/3/5 (they'll be displayed in such a way so that they'll line up so you'll be able easily tell how they are in each area. 

So if you battling the Drengin Empire for most of the game and both of you are going after beam weapons (phasors, disruptors, that sort of thing) you might have ships with attacks like: 10/2/1 and Defense: 7/3/3 (beam/mass driver/missiles and shields/armor/point defense).  But then if you battle the Torians they may be big in mass drivers and things can change in a heart beat. So you'll have to put some more thought (and so will the computer players) into who you go to war with.

Fleets won't be that common until later in the game since your logistics ability starts out at 0 and even a trivial ship uses 1 point of logistics. It'll take awhile to get say 5 points of logistics but a battle ship might use 5 points of logistics.

Based on your various choices of weapons, defenses, propulsion, hulls, skins, etc. your ships will look quite different. Far more customization than any game of this kind that I'm aware of. And you'll be able to also look at ships and eventually be able to just tell what kinds of weapons they're strong on visually (i.e. once you are familiar with what things look like on ships).

The goal is to have combat have a lot more depth to it strategically without making the game overly complex. Seems like most strategy games these days get way into tactics -- which is fine. But GalCiv will be a game of strategic decisions, not tactical micro management.  So keeping an eye on what the various races are doing will matter more here but even in fleet battle, it'll just be a straight up ships from fleet 1 fire, ships from fleet 2 fire and so forth).