I've been seeing this speculation for more than a week. Show me the game exists and give me details, and then I might experience a flicker of excitement. Otherwise I'll pass.
I see people hoping that it will be set in modern times. So-called Thief fans wanting the next game to be set in modern day America. What kind of crazy talk is that?! You would lose everything which makes Thief Thief!
Tiny levels. Lots of loading. I curse the xbox and the decision to port the game to it. The console might have been comparatively powerful but it did not have enough RAM to cope with sprawling PC style levels. Personally, I also disliked the City. Having to sneak through the same small, limited streets between missions, needing to scurry around to work out where your next mission was supposed to be ... eh, no. It was an idea which couldn't work with the technology they used.
I don't hate it as much as the others here. I never played far enough to hate it; I drifted away after a few missions. Yes, that means I never played the infamous Cradle level.
Bookmarks