Well, I'm around 5 hours in and at this stage I think I'm in love with this game. It's like System Shock 2 with more of a pulse...that would turn off some I guess but I actually think I like this better than SS2 so far. The game is very linear though, I think you mainly have to backtrack only to unlock secrets with your new powers a la Zelda, but that doesn't bother me cause the story, setting and combat are so damn good. I think to call this a straight-up shooter is ignoring all the thought that's put into every room and all the options you have in combat. In short, this game rocks and unless it runs out of ideas I'll still be ranting about it after I'm finished. Awesome.
Btw I think we should keep this thread free of spoilers...I know there are some whoppers in the game