NGTM-1R: The new subfactions all play very differently, even when they share a race, and play styles from rushing to turtling to diplomacy are supported depending on faction choice. The Titans are your generic superships that wreck fleets by themselves. Corvettes are rapid skirmisher units. The graphics got a major overhaul so everything's prettier than ever, and that's everything from particles to shaders, including shadows. The added capital ships all have some nifty new features, and abilities now have four levels instead of the three they did in Trinity. The new victory conditions are diverse, such as Research Victory being the tech-to-win condition and Occupation is the King of the Hill win condition, whereas Flagship is the Assassination victory and Last Capital Standing is where you're eliminated if your capital planet goes under. The engine also got optimized for better performance, and there's all sorts of new stuff like buffs can now be dependent on other buffs and planets can be stripped for resources so modders will have a field day with it.
Mort: Yes, it is.