there's a bug after where the second statue amulet is, that there is no way of going back to the statue room, I call it a bug but there Simply no way of going back after you escaped the hall where the Gray haired girl is at.
Viewing post in Drain Mansion - Free Version comments
after you get the second amulet (those that you put in the statues) you have to go back through the place before the corridor with the gray haired girl, but there isn't any way to avoid the girl at the bottom, forcing a strugle escape but I already had some "damage" in me, making it impossible to do it.