Does Civilization IV:beyond the sword just add more game options?

I have ordered Civilization IV: Beyond the sword and im wondering does it has all the game play from Civilization IV and more or has it got all its own units and game play? please help :)Does Civilization IV:beyond the sword just add more game options?
It offers new everything, new leaders, new civ's, new units new buildings including wonders, but the most important additions are corporations and scenarios, like the space based "Final Frontier" where you colonize star systems rather than cities, or "After World" which plays more like an RPG than a Civ game, it is a great expansion pack if you have civ 4 already then I would highly recommend getting Beyond the Sword.Does Civilization IV:beyond the sword just add more game options?
its an expansion, so you're still playing civ4. it just has more civs, leaders, wonders, etc. plus there is more emphasis on espionoage. but you don't really have to re-learn anything.

used boats

planet hollywood