I'm not entirly sure where to put this, so I decided to post it here.
"Adding this much new life to what should be a very familiar game is an
amazing achievement. While no single addition here can be said to make
this expansion, the scope of the subtle yet wide-ranging changes
greatly improve the Galactic Civilizations II experience. Before
Twilight of the Arnor, players could stick to the Terrans and encounter
everything that the game had to offer. Now, you deal with something new
each and every time you go galaxy conquering with a different alien
race, which freshens up a game that was in need of exactly this kind of
facelift."
The review is very much postive.