Galactic Civilizations II: Dark Avatar expansion

The most intriguing of these additions is the ability for players not only to custom-craft their own faction's looks and ship designs, but also to do the same for their enemies. The in-game ship editor is versatile and detailed enough for players to set up sci-fi showdowns between titanic franchises like Star Wars vs. Star Trek or Babylon 5 vs. Battlestar Galactica.

The intelligence of your opponents can also be tailor-made in a way that falls outside of the commonly found easy/normal/hard system. AI is broken out into many different attributes. For example, you can create a stupid enemy who is flooded with finances, or an extremely shrewd one that tries to thwart you diplomatically. This level of customization is possible across the galaxy, enabling you to populate the universe with adversaries who will offer you the most fun and challenging rivalries.