"Dead or Alive 4 (DOA4) is a fighting game developed by Team Ninja for the Xbox 360 video game console. As the latest entry in the Dead or Alive video game series, its plot follows the events of the 2001 title Dead or Alive 3. The game features 22 playable characters and many multi-tiered and interactive fighting arenas.
The game has a number of updates in reference to previous titles. The counter system has been tightened, making the window for counters shorter and more difficult to execute. The amount of damage that counters inflict has been changed. In Dead or Alive Ultimate, the counters were rather damaging and in Dead or Alive 3, the amount was much less, relying on players to strike or throw more to defeat their opponents. Characters' movelists have been vastly updated as well. Finally, four new characters have been added to the fighting roster, with returns from a couple of past characters as well."
Source: Wikipedia, "Dead_or_Alive_4," available under the CC-BY-SA License.