These are the key features and I'm unsure if the multi-player has been enhanced or not in the US release.
Key Features
* Ultimate hardcore RPG challenge -- In this brutal land, death is inevitable, but not final. Combining the best features of an action game and RPG, you'll slice, smash, shoot, and ensorcel some of the most horrible, vicious enemies ever encountered. Are you strong enough to face the impossible and win?
* Ground-breaking online capabilities -- Network features go far beyond any previous RPG, allowing players to leave hints for each other, replay death scenes, cooperatively revive dead players, or invade another player's game to wreak havoc. Not merely an add-on feature, multiplayer options are vast, and uniquely focused on changing and intensifying the single player experience.
* Freeform and flexible -- The open-ended structure of the game means that there is no single path, but rather a wealth of options. Set your own pace and progress as you like. Build exactly the character you want by creating a detailed avatar, nurturing the right stats, and customizing your skills and equipment.
* You act, the world reacts -- The World Tendency system changes the aggressiveness of monsters and the rewards for killing them based on players' actions. Different events and NPCs may be triggered, as well.
Demon's Souls has not yet been rated by the ESRB.