I have an admission to make: I have never played a Deus Ex game. But I wish I had, after experiencing a brief encounter with Deus Ex: Human Revolution. The first game promised a game world centered around the consequence of your actions -- and a decade later, the concept is still fascinating. To showcase the versatility of the game world, I got to see one level, played three different ways.
Set in a futuristic Detroit, you'll assume the role of Adam Jensen. There's a chip you must recover, but it's hidden in a corpse locked away in the police station's morgue. How are you going to retrieve the data? Shooting your way in is the last resort, you're told over a communication device. Considering the number of (innocent) police officers stationed there, that's wise advice. You can walk into the front door, but only if you have the right conversational skills.
A former partner of Jensen's is the receptionist, demoted for something related to your past. Somehow, you'll have to gain his favor by choosing the appropriate dialogue commands. When given a choice in the conversation, you'll see big key words appear on the screen, not unlike in Mass Effect. A quick glance should give you an idea of the end result, but Human Revolution goes a step further by providing your full response at the bottom of the screen. That way, there's no confusion over what your character will say when selecting an option.