Great game with lots of fun subquests and mechanics, but hampered by the blackmail being hard to believe considering the protagonist is 1) clearly unwilling initially, and 2) vastly more powerful.
That said I do think some people are exaggerating how bad it is. Yes of course Iroha is going to fight Okane. They're supposed to kill each other by the rules of the death game. The rules of the death game take precedence over any other drama at school. Iroha killing Okane isn't "her siding with her abuser". It's her doing what literally anyone with a brain would do: survive. It's the weakest moment in the game's writing to be sure, but I still wouldn't describe it as Iroha siding with the abuser.
There's no way to give your virginity to Potaku-kun or one of the Succubi, is there? If so, unfortunate.