This new sequel features 4 totally new characters and one new boss (Princess Sissy). However, Angela does not return in this game. Jimmy, Elias, Lynn and Jones from Rage of the Dragons are guest stars, and are unlockable. A few of the game elements were borrowed from this same game as well. The western releases drop the Shin Gouketsuji Ichizoku title and remains named simply as Matrimelee. It was one of the last few games to be released on the Neo-Geo.
Transformations were excluded, and a few of the characters from the previous sequel do not appear. The Stress meter now could be filled up to three levels. Every character has a Stress Shot (1 bar), an Ippatsu Ougi (2 bars) and a powerful, hidden super attack called a Kinjite (3 bars). However, only a few of the Kinjite moves are known; information on the rest have not been released by Atlus or Noise Factory.
Source: Wikipedia, "Power Instinct", available under the CC-BY-SA License.