I have been and will always be fascinated with virtual worlds. Back when Doom was new, I used to load up empty "Deathmatches" just so I could explore the levels in detail. I did the same with Duke Nukem 3D and later Quake. When I was able to first play Myst, my favorite thing to do was just walk around and explore the various "ages" as much as I could.
I've always been fascinated with experiencing places that don't exist.
So when I discovered Castlerama a few days ago, I was very excited. Castlerama, a free app for the iPad and iPhone, is merely a small, virtual town you can walk around. Powered by the Unreal engine, there really isn't that much to it. As far as I can tell, the only building you can enter is the Church (the Catacombs also load as another map, but that one has a more obvious entrance), but I've still spent a lot of time going through every inch of space.
I also have been playing around with Epic Citadel on my iPad too, which is an older tech demo released using the Unreal engine. Epic Citadel allows you to explore a medieval town. This particular app was made to show off the technology prior to the release of Epic's Infinity Blade... but here's the thing - I'm much more interested in exploring the virtual world than I am fighting monsters.
What apps like Castlerama make me hungry for though is a Myst-like experience in that sort of environment. A relaxing game where there is no time pressure, no one chasing me... just a puzzle to solve and a world to explore. Honestly, I get stressed out when there's an active antagonist, and I just want to sit back and play something on my own time.
I hope this is where the designers of Castlerama take this technology. If not them, then hopefully someone else will do so.
As weird as this may be. I share a same fascination. When I used to have Star Trek Elite Force, I'd love to walk on the USS Voyager when I could I was fascinated by being able to walk into random places whenever I could do that in the game. It was just fascinating to have the power to walk into a room when i wanted too. So I too can understand what your interest is.