For an expansion pack, Twilight of the Arnor is ridiculously deep. Building on the improvements of last year's Dark Avatar expansion are an all-new campaign, some impressive visual upgrades, and numerous fresh gameplay tweaks - including a new "Ascension" victory condition and an imposing Death Star-style superweapon. (There are also six standalone bonus editors for making your own mods).
This sandbox is so big that you could literally get lost for months as you colonize and terraform hundreds of far-flung worlds, develop huge space fleets, research scores of new techs, and wage war or strike treaties with up to nine neighboring civilizations. The ability to play as any of the 12 featured races - each now featuring its own unique technology tree, planetary improvements, and spacecraft - expands the gameplay experience from deep to damn near bottomless.