Childrens games featuring questionable material

[Kirin]

This is a question that was actually refereed to me by a newly qualified teacher at my workplace, one which admittedly I can't answer but falls in my area to sort out.

There's a computer game at the moment a lot of children at my school appear to have fallen in love with called "Undertale". Now I don't know everything about it, I thought it was just some crap from Japan like Pokemon but from what I gather this game features at least two instances of homosexual couplings of monstrous like cartoon creatures. There's also one character who while not homosexual takes the form of a male robot and is overtly camp (addressing everyone as "Darling", "Sweetheart" or "Gorgeous") and is seen cross dressing at one point. In both instances  the player has a role in the couples getting together, and to "win" the game and get the right ending the player must ensure both of these couples get together and that the robot becomes a TV star.

Until earlier today when doing a google search after having a concern raised I didn't know anything about this. There are children in my school who have stuffed toys and bags featuring depictions of characters from this game. The teacher in question only raised a flag after she was going to use it as part of an RE lesson (the games lore apparently states clearly that only humans have immortal souls, and when non-humans die their souls just vanish).

I'm not really sure what action if any to take, considering this is a Catholic establishment. I know the Catholic church doesn't mind dramatizations of bad things in literature, and I'm tempted to ascribe this game under that pretext. However, as far as I know the gay couples in this game, along with the robot are portrayed as good guys or at least not malicious.

To my knowledge some of the older children play it at lunchtime and most of them seem to know of it. What would you expect from a Catholic school? Would you want it banned from the premises? A letter sent out warning people about it? I'm fishing for ideas really, since I organize pastoral operations here and whatever I say will happen but obviously I would prefer the decision to support the ethos of the school.