Power Instinct 2 features five new characters, giving a total of 13 playable characters and one unplayable boss (Otane Goketsuji). The PlayStation version, retitled Gouketsuji Ichizoku 2: Chotto Dake Saikyou Densetsu, was only released in Japan and has some characteristics from Gogetsuji Legends (as it shares almost the same subtitle to its Japanese version), like the team battle and the possibility to play as Chuck and Kuroko, but these features are only available for Versus (player vs. player) mode.
Introduction of the "Stress" meter into the series, which increases when one's attacks are blocked or when attacked. A super attack can be executed when it is full. In addition, when the Stress meter fills up, a character becomes engulfed in a flame of their own energy for a brief moment, which protects from any incoming attacks from the opponent and knocks them away if they are too close.
Source: Wikipedia, "Power Instinct", available under the CC-BY-SA License.