Probably the only one in existence. Interesting interviews with the creators. I think he jumps to a few conclusion in the game summaries though. It was a long time ago, but I think this page (or a previous incarnation of it) was where I first learned that the third game was supposed to take place in London. There are two posters in the Cable Car Barn of Manhunter 2. The first was the cover of the first game. I never could figure out what the second one was supposed to be. It was only after learning that London was planned for Manhunter 3 did I recognize the poster as Tower Bridge.
One thing I still don't understand is why they changed the Orbs (or at least introduced a new Orb species) in Manhunter 2.