Injuu Genmu 2 ~Brain Burst

There is no real story in Injū Genmu II: Brain Burst!!; the setting is a certain magical land where three young, pretty, female magical creatures hold a contest. Innocent young girls will test the knowledge of the participant, and should he win, he will be treated to... a blood-chilling spectacle of said girl being raped by a tentacle monster.

[From Mobygames]