Regarding the new factions, I was surprised how different they felt. At first blush, they aren't much more than palette swaps--simple retreads with different Titans. In this case though, the technology really makes a difference. The Terran Loyalists, for instance, are basically turtles, which is exemplified by their tank of a Titan and their increased focus on star base defenses. The Rebels, however, have powerful offensive improvements for their ships, as well as the ability to sic pirates on opposing factions. Other races bring their own variants to the table, whether in the ability to destroy whole fleets with the power of mass suicide (no really), or strip planets to the core and leave them lifeless husks. It would be overstating matters to suggest that these new factions lend Sins of a Solar Empire the depth of a Galactic Civilizations II, but it's certainly a welcome improvement (even if the race balance could still use some tuning--the ability to jump star bases make the Vasari Rebels frighteningly powerful). Ultimately, Sins of a Solar Empire is still a real-time strategy game, meaning that Ironclad has to take care lest it all become too overwhelming. But the new factions and objectives do add a certain amount of depth that wasn't there before, and make massive games set in huge galaxies much more in appealing. For that reason, Sins of a Solar Empire Rebellion is an essential addition for existing fans, and a great opportunity for newbies to jump in and try it for themselves. For many, the Titans will be the key selling point, and it's true that it's hard to deny the power of rolling up to an enemy home world with a five-mile long monstrosity and simply ending them. For the first time ever though, naked force is not the only option, making Titans a fun (albeit very useful) bonus more than anything. And that is the most important improvement of all.
Have fun blowing up all the new factions.
This Sins of a Solar Empire: Rebellion review was based on a digital version of the game supplied by the publisher.