Galactic Civilizations II: Twilight of the Arnor points out one of the problems with reviewing certain expansion packs. Everything is so tightly integrated into the core game, which hasn't changed much, that it can be hard to distinguish what is new, what is improved, and what is simply brilliant design from six or 12 months ago. It's as if we've been invited to play a single game that is continually a work in progress; sort of a digital Calvinball with Stardock popping up every now and then to tell us that about some new rules to consider.

From a certain perspective, Twilight of the Arnor is not really an expansion pack. Yes, it adds content, and yes, the story that began in the original Galactic Civilizations II draws to a close, but calling Arnor an expansion pack sidesteps the unusual development of GalCiv 2. At first glance, it looks like the traditional release pattern of a core game with expansions adding new content, but that's not what's going on at all. This is not a matter of A + B + C. This is A1, A2, A3, a phased rollout of what is now one of the best strategy games ever made.

The rollout is best seen in the way the different races have been handled. The core game had generic aliens that looked different but played pretty much the same. The first expansion, Dark Avatar, gave them different artificial intelligences and preferences making conquering the universe a different experience depending on whom you got as a neighbor. Now, in Arnor, every faction has unique buildings and a couple of unique branches on the tech trees, further differentiating the races. The Thalans, for example, can research super-durable hulls via the Hyperion Shipyard, but their early buildings are one-per-planet structures.

With so many new buildings, it can be hard to keep track of which structures do what. What is the precise production difference between a slave pit and a traditional factory, for example? How important is this religious tech? The exploration is part of the fun, of course. The new variety is more apparent in the way that you play the game than in how the enemy races deal with you, but the tech trees work to make the enlightened races more enlightened and the evil races more evil. Races with morale bonuses can now raise those taxes even higher. The once generic universe of Galactic Civilizations is now rich with variety.

There is also a new way to end the game. Ascension Crystals are scattered throughout the galaxy like other resources and you can collect points towards godhood by plopping a starbase on these crystals. A handy apotheosis countdown timer tracks who is closest to ascension. You can't fortify these starbases, so they are easy targets, but you don't want to start a war for which you aren't prepared. The ascension countdown gives you something else to consider when you decide which empire is next on your chopping block.

In general, your computer opponents are much more cognizant of how close you or someone else is to victory. You will occasionally get balance-of-power wars where half the galaxy decides that someone else is a threat and sets out to remove the peril, so you get an outer-space coalition of the willing if that ascension timer gets within a couple of hundred turns of victory.

There's a nice shine on things, too. The ships look sharper, and there are new bits to add to your custom designed vessels. GalCiv has never trafficked in impressive visuals, as can still be seen in the retro look of the land battle screen, but it looks much better than it once did. There is more color, more light and consequently more detail and variation in the universe.

You do get the third chapter in what is, frankly, an uninteresting space story. You get a new Immense size galaxy option, a size that is probably a step or two beyond my own patience. And, for the first time that I can recall, you get stability problems that lead to random crashes and prevent you from alt-tabbing. New ship options and Terror Stars add some new things to consider in warfare, and Stardock has added greater user customization through advanced editing tools -- tools that will lead inexorably to "Star Trek" and "Babylon 5" mods before anything truly original.

But Arnor is not about novelty so much as it is about completeness, and the added depth to the GalCiv universe brings it alive in a way reminiscent of the cosmology of Master of Orion or Star Control 2. What was once merely a great strategy game with all the appropriate resource collection and fleet management is now a universe where one race can trade secret unique technologies to give allies a leg up on the competition, where you can use the ability customization to either accent or balance your race's strengths, where you eventually develop irrational hatreds of specific AI-controlled powers for no other reason than that they are a constant pain in your side game after game after game.

If you missed Galactic Civilizations II the first time around, you will want to start with the most up-to-date version, of course. If you've lapsed in your pursuit of Drengin Manifest Destiny, Twilight of the Arnor has enough new stuff to bring you back and keep you for a while. While it was always good, Galactic Civilizations II now feels complete.

This review was based on a retail copy of the game provided by the publisher.