https://motherboard.vice.com/en_us/article/j5k4gp/dead-or-alive-6-is-going-to-chill-on-the-boob-stufffor-now

You can like the Dead or Alive fighting game series for how it plays, you can argue that it's substantially different or even better than other fighting games for reasons that have nothing to do with its character design, but there's no denying that it's the 3D fighting game that's known for its boobs, and specifically its boob motion physics.

The design of the female characters in Dead or Alive was such a draw, that at some point publisher Koei Tecmo spun those characters out to their own game where they romp around a beach resort and play volleyball in bikinis. The technology that makes the boobs in the game jiggle (Koei Tecmo previously called this the "Softness Engine") was so precious to Dead or Alive, its developers were worried about what players and modders might do with it one Dead or Alive 5: Last Round was released on PC.