Two Worlds is an open world RPG similar to Oblivion. If all the PR hype is to be believed it could be just as good as Oblivion as well. The developers make the claim that players can choose their own path through the story and the world will change along with their decisions. The choices you make will determine what choices are available to you in the future.
Players choose what class to play when they create their character but all skills are available to all classes and if you don't like the choices you made while advancing your character you can visit one of the game's "career changers" to respec into something else.
Combat is similar to what you would find in most MMO's with some attacks occurring automatically while the player chooses when to use special attacks or abilities.
One thing Two Worlds has that Oblivion does not is the ability to play online with up to 7 other people. The multi-player mode and open ended game play may give Two Worlds greater appeal and staying power.
The game appears to have everything needed to be an enjoyable experience. If they are able to capitalize on the player's ability to pick sides and influence the world it could be a very interesting game to play particularly in multi-player.