I'm a librarian who loves anime, manga, and reading a wide variety of genres.
This is more readable than I expected, although I'm still getting "Gabriel Knight gameplay" flashes. For example, at one point Gabriel is in Detective Mosely's office and starts talking about how hot it is, which leads to Mosely feeling sympathetically hot and taking off his jacket. Then Gabriel asks if he could have a cup of coffee (who complains about being hot and then immediately asks for a cup of coffee?), so Mosely leaves the office to go get one for him, providing Gabriel with the opportunity to steal his badge. He then uses that badge to gain entrance into a rich and reclusive woman's home, because he has the hots for her and wanted to see her again (it's fairly obvious that she's magically messing with Gabriel's head, not that he's caught on to that yet).
This is the kind of step-by-step puzzle that the Gabriel Knight games were riddled with - it fit nicely into the story and felt more natural than, say, suddenly playing a random sliding puzzle in order to be given the badge, but it's still not natural enough to work in a book as-is.
At any rate, I checked Steam to see whether any of the Gabriel Knight games were available (I probably still have the CDs for the second and third games, although I don't know that they'll work on a Windows 7 computer). Surprisingly, this one is on Steam - I just don't want to pay $19.99 for it.