As cool as the original Dead or Alive was, it was still little more than just a retolling of the standard 3D fighter created by Sega. Powered by the new Naomi hardware, Dead or Alive 2 really pushed the boundaries of what these games would eventually become. The character models have obviously been redone from scratch to look massively better, not only technically but on an artistic level as well. All of the graphics look amazingly better than the CG intro from the original Dead or Alive - better than the CG intros in pretty much every PSOne game, for that matter. But that wasn't even the real star. The big thing about Dead or Alive 2 were the multi-tiered fighting arenas. Samurai Shodown 64 was technically the first game to do it, but Dead or Alive 2 really popularized it and made it feel especially badassed. These weren't enclosed cages or plateaus or even rings - you fight on a skyscraper, in the Japanese wilderness, in the bell tower of a chapel. They're littered with columns, changes in elevation, all of kinds of features that made the game feel so much more alive. And the intensity of the action triples when you first knock an opponent off of a cliff or out of a window, then leap down after them and begin fighting on a ledge below. The rather bizarre structure of the single player mode means that you'll rarely get to see these arenas in full, though—each match lasts only one round, and they're usually over in a matter of seconds.
The gameplay evolution picks up where Dead or Alive++ left, although you can now move in full 3D. Using the directional pad lets you use regular 2D controls, while the analog stick is used to circle the opponent, something that adds greatly to the strategy. Practically all of the cast from the original returns (except Bayman, at least for the initial versions), with a few additions: Helena, the opera singer; Ein, the pretty boy; and Tengu, the monstrous main boss. The tag mode introduced in DOA++ got a major overhaul, now allowing instant swaps and powerful team attacks, and would become very popular amongst fans of the series. So popular in fact that Team Ninja was considering to make it the main play mode for further sequels. This is where DOA really began to hit its stride as a series deserving of respect.
Dead or Alive 2 (Dreamcast)
The release history of Dead or Alive 2 borders on utter ridiculousness. The original release came out in October 1999 in Japanese arcades, then it was ported in April of 2000 for the Dreamcast in America. While it was a superb game, it still lacked much in the way of endings or the extra costumes that made the original so enjoyable. It hit the PS2 in Japan later in the summer - and while it added some more backgrounds and costumes, the designers clearly weren't very comfortable with the new hardware. The graphics are extremely jaggy, and while the cutscenes run smoother, everything as a whole just looks much worse. The next Version was the European release for Dreamcast, that also had some interesting costumes, like a Shadowman outfit for Zack (it was published by Acclaim, who also made the Shadowman game), but still inferior in content to the PS2 version. Not long after this, it was finally released in Japan on the Dreamcast, with all the costumes that were added to the PS2 version. It has also two new backgrounds that for some reason are different from the PS2 ones, but without the graphical detriments. The biggest improvement this time was the inclusion of two unlockable characters (Bayman from the first game, and the boss character Tengu). There was also a "Limited Edition" released simultaneously, but the only difference was in the cover art. This version was the only console upgrade (and the last DOA game over all) that made its way back into the arcades as Dead or Alive 2 Millenium.
In October of 2000, Dead or Alive 2: Hardcore was released in America. A few minor modes were added, including a battle recording mode and a UPS system that let you save player stats. Mostly though, it fixes some of the graphical problems of the original PS2 release, although some jaggies are still noticeable in high motion. It also includes even more costumes, more story scenes, more backgrounds, and some utterly hilarious English voice acting. Finally, in December 2000, Dead or Alive 2 Hardcore made it back to Japan, with yet more extra costumes, story scenes and gallery pictures. This version formed the basis for the European PlayStation 2 release, which was just labeled Dead or Alive 2, without the "Hardcore" suffix. And it's still not over. In 2004 - five years after the original release - Tecmo released Dead or Alive Ultimate - which is the definitive version of Dead or Alive 2, with better graphics (running on the technology from Xtreme Beach Volleyball), even more costumes and backgrounds and, most importantly, online play. More info on that is found below.
The Dreamcast version of the game had a hidden cinema in the intro - if you put in a code, you could unlock a scene where you'd see a naked Kasumi getting cloned. Naturally, most of it was hidden to prevent any adult content rating, but with a Game Shark, you can use this model in the actual game. This kinda screws up the game, but it's funny to see that they actually modeled nipples on her.
Dead or Alive (Dreamcast)
The opening song Exciter is rather well known for its incredibly incomprehensible English. Anime Lyrics has done a fine job of attempting to transliterate them, which given the mumbling, is easier said than done. Here's some lines:
I just wanna be Exciter
A herd of Domestic dog, Cheap trick
Hide your drastic desire
I still stay there with a finger in my mouth
Classic. The folks who brought you this is a Japanese group known as "Bomb Factory", who are presently still around.