The game begins on the culmination of what has apparently been many, many years of careful plotting and preparation. Our hero is set to slip into the mansion of the Confessor Destine, discover what shocking secrets he can (he needs seven to cause sufficient disgrace) and slip out again, leaving no trace.
I'm reminded of "Lord Bellwater's Secret", from IFcomp 2007. There, too, there was a lot of hunting for information, but "Sub Rosa" covers more ground. We're not limited to a single room, and so the game feels less dense; puzzles tend to be more mechanical in nature, and less dependant on information learnt enroute, though there is still some of that. The world, too, is fantasy rather than historical: in place of period accuracy and trivia, we have worldbuilding. And I find the worldbuilding here to be both fascinating and well-handled. There is a temptattion, I think, when building a new world to try and explain everything about it. Here, while a signicant amount of information is conveyed to the player, it never feels as though the author were taking time out to clarify minutiae; we're given just enough to get us through, and allowed to infer the non-essentials. This actually adds to the sense of realism and immersion.
I liked most of the puzzles, which were a very varied bunch. The one puzzle I did not like was the clue obtained from the quailer, in which we're told that "a different syllable in each line" of its song has been stressed. It should be trivial for a listener to note which syllables have been emphasised, but we the players are not given this information. It's basically making a non-puzzle into a puzzle via the medium, and that annoys me.
On the whole though (puzzles that shouldn't be puzzles notwithstanding) I found the overall game to be much like a bagel-and-lox Benedict: satisfying, artfully put together, just different enough to be notable but you still instinctively know how it works. Fruit on the side with English cream, orange juice, and a warm hazelnut blend of coffee.