Better graphics, Epic miracles, but some really important stuff were left behind.
When the sequel was announced, I upgraded my computer just for it. I was really looking forward to play.
When I first get the game, first deception comes in: "Oh, where are the skirmish and on-line modes?"
When I started to play, a second deception: "No other gods? Hum, ok, we have the tribe leaders, they somehow have epic miracles and creatures... So, fine. " Besides, some time latter, "Battle of Gods" was announced, and this problem got half solved. (Just one God, though. I kind of missed the whole allies and enemies from B&W 1, and the suspense, "last boss" feel that Nemesis had. Actually, the whole plot is better and more exciting at the original game.)
Despite this, the gameplay is a little better on my opinion. The "menu bar" makes it easy to select buildings and miracles, the new army system is really cool, too.
The creature graphics are also amazing, if you compare it to B&W 1.
I've covered the pro's and con's. Now I'm entering in a neutral zone.
What I mean is, some people will like this and some, like me, will hate it.
The game is much more easy than before. The logic puzzles where mostly replaced for "arcade" mini-games (no more fun on the tree puzzle, guys.), which, by the way, are not entertaining at all to me. (Found myself just skipping all silver scrolls after some time.).
It's also really easy to be the Good-guy, unlike at the original, where you had your influence ring and had to figure out how to impress towns outside it (including without your creature at a certain point). It was challenging, and I loved it. Now you can just mind your own business and other towns will eventually come to you. No multiple-village administration needed, no actual effort needed.
So, this is my opinion on this one. "I like the first one better" was my overall reaction.