A very mental game ....
Having said that, the game isn't without it's good points. It's got a lot of game time, so much in fact, that you almost always run out of both patience and interest long before you finish the game. I think the best word I can use to describe the game here, is ponderous.
Once you have a sizeable empire going, don't expect a speedy game. It can take as much as 5 - 8 minutes to work your way through all the details that crop up ... and if you don't, you won't have much of an empire.
The space combat system has been upgraded substantially. Rather than being turn-based as in the past, it is now real time - and it does seem to pay a lot of attention to physics ... battles are a lot more realistic ... but also more difficult to control and follow. In the end you may just want to let the computer deal with all the details.
The game has improved in the graphics department, but that's all I can really say about that. The aliens look suitably ... well, alien ... but the one place where the game has slipped quite a lot is the diplomacy screen. Try reading the dialogue, it doesn't make sense most of the time - making it seem as if the programmers had rushed it in at the last minute.
In the end this is more of a government training excercise than an actual game, and if you actually manage to finish it (and win...) you'll be uniquely qualified to run a country at the very least.
In fact, right now I could point out a couple of governments who could use the extra experience ...