Don't think she can be beat in the standalone version, at least I couldn't and that makes perfect sense cuz once you beat her you should be able to move between floors right? Well that's not possible as long as this is a standalone and has not been integrated with the actual game yet. This is why in the final battle you don't see Iris's hp either, because she can't be beat anyway, just like Karen against whom you can just survive, her hp remains intact. No matter what you throw at her, she takes 0 damage. In Iris's case the hp is not even there to gauge progress in the final stage lol. Also the only ending I could achieve is the afterlife ending and that was game over. Maybe someone else can shed some light on whether there are other endings.