One or more of the heroine is a classic Tsundere (as they were defined before the anime "mainstream" assimilated it).

Starts tsuntsun (cranky, violent and possibly violent) towards the protagonist (and possibly everyone else), due to some reason or another, and over the course of the game falls in love with him/turns deredere (lovestruck) .

While tsuntsun and deredere might conflict, this phase will be over after a short while and progress into straight deredere.

Compare with Coodere. Do not confuse with Modern Tsundere.