Of course you can. In fact, the Dieties and Demigodshandbook gives you a complete combat profile for all of the gods in the D&D, Olympic, Norse, and Egyptian Pantheons. Most of them can be easily handled at epic levels.
Dungeons and Dragons.
no
While Dungeons & Dragons shares some characteristics with Alternate Reality Games, it is much better classified as a Tabletop Role-Playing game. There are firm rules in place for players in Dungeons & Dragons whereas ARGs have loose guidelines for them. ARGs also do not require players to assume alternate identities, or even to roleplay, which is the foundation of any Dungeons & Dragons game.
They have Dungeons and Dragons branded games for the DSI. You can buy them at any gaming store. You cannot, however, play tabletop Dungeons and Dragons on a dsi; they are two different gaming concepts (videogame and tabletop game).
Dungeons and dragons is a whole rules system, first and foremost for a pen and paper game, so apart from loaded dice it's hard to say. There's also a lot of computer games based on dungeons and dragons, so if it's one of those the question is about, please specify the question.
Dungeons and Dragons Online
There is currently no fourth-edition D&D game for any system and there has been no announcements of plans to do so.
There are plenty of mortals that Zeus killed, but he did not kill any gods or goddesses.
Neverwinter Nights 2 is an offline RPG built entirely around the d20 system. For the PSP there is also Dungeons and Dragons Tactics. By the way: Neverwinter Nights 2 is "slow" real time, while D&D Tactics is turn based.
it can kill any human !! in a minute
any world they are all the same
To play Dungeons and Dragons: Castle Ravenloft, you need the Castle Ravenloft board game itself, which includes the game components and rules. Additionally, having a set of polyhedral dice is essential for gameplay. If you're new to Dungeons & Dragons, a basic understanding of the rules or a rulebook would be helpful, but the Castle Ravenloft game typically includes the necessary rules to get started.