Galactic Civilizations II: Dark Avatar Review

Perhaps the most significant and satisfying gameplay change is the inclusion of environmental restrictions for colonization. In Dread Lords we, like many players, preferred to grab as many habitable planets as possible before worrying too much about things like infrastructure or technology or warships. Sure, it sometimes left you open for a massive attack, but it was the surest way to establish a solid foundation for the middle game.
This time around many of the planets are off-limits until you've researched the technology required to colonize them. And since there are different technologies for different environmental hazards, you'll really have to choose carefully. These technologies are also relatively expensive as well, so any effort you put into researching them is going to mean you're neglecting something else. In all it's an excellent way to kind of put a check on the colony rush that most players have been using.