Thief is the upcoming reboot of the classic stealth action series.
Steal a glance at Greg Tito's full preview here:
It may have just been the demo, but it seemed the guards were intent on not seeing Garrett as he moved about the courtyard. Perhaps that's because of the addition of a gameplay system called focus, which seemed to let Garrett get away with anything. Focus is essentially mana, and it's consumed when you enter a mode that somehow heightens your senses to the point where you can see footsteps through obstructions. Focus makes everything easier, from picking pockets and locks to rushing from shadow to shadow without being seen. It honestly appears to be a cheat mode, so I was thankful when Stephen Gallagher from Eidos Montreal said you could turn it off in the menus.
At least focus doesn't automatically regenerate. You have to collect poppy flowers to replenish it just like you need food packets to get back your health. It's nice to have a scarcity of resources in a game like Thief, but of course that means you as the player might feel compelled to look in every crate or box you find. I know I will.