When it comes to storytelling and gameplay it's simply the BEST part of the series. I loved how the story developed, how new locations become available one after another during investigation. Music was also great, spooky at times, very atmospheric. What I didn't like however was the graphics. It was inconsistent, part low- part hi-res, it looked a bit too messy for me. In my opinion backgrounds looked far worse that in previous games, particularly in part three (best looking Blackwell game). Here, they seemed sort of steril and empty. Kinda dull old 3DStudio-ish(Psychic street and Night Club for example). I don't know, maybe it's just the matter of preference. I just don't like the type.
But overall, this is a really great game (and a very long one at that!).

Nice visuals and music, plot and puzzles work well. Very few inventory-based puzzles and perhaps the puzzles were a little on the easy side, but overall a quality adventure game.