I could not recommend this game highly enough...
As many have stated, and I will state, it is a game that will reside on your computer until one of two occurrences: (a) Dominions(x+1) comes out OR
(b) some fickle pretender to deific grace decides enough is enough and wipes your hard drive for the affront to contest it's sole claim to deity from the portal in your computer.
Honestly, I play many games, and, particularly if you do not play MMO style games, it is a game you will play and play and play.
Learning Curve: Steep
Replay Valuable: Going to positive infinity.
Just playing EACH nation in each era ONCE will take more time than a lot of people spend on a game.
Simply put, it's just THAT good. Of course, we're die-hards, so take it with a wee grain of salt.
Wyatt Hebert