The base game consists of watching a snobbish, affected character reminisce about their past experiences as a womanizer and (Spoiler - click to show)serial killer. That, by itself, is a perfectly fine secret for the game to hide, even if it hides it VERY badly. (It's self-evident if you're paying attention, but there's also an item hidden in the scenery that, (Spoiler - click to show)if picked up just before the ending and brought along, reveals it beyond all doubt.)
The problem is that you will end the game with a score of 3/10. In order to get the full 10 points you need to identify the character's minority by using every opportunity to examine the possibility, no matter how little sense the actions make in context. (Spoiler - click to show)In the biz, we call this "transvestigation," and it's a hateful, reviled practice. What's more, if you pay VERY close attention, there's a very strong implication that (Spoiler - click to show)being a transgender man has a Freudian connection to their murders.
Vile. Very well-written, but vile.
I suppose I also should point out disambiguation problems with the towel/towel rack, too many potentially useful commands (like trying to examine parts of a room) routed back to LOOK, but just ... after that revelation my heart's just not in it. Can't a girl just enjoy some sleazy horror without having to deal with this garbage?