It’s always interesting reading an interview with Warren Spector. Call me a fanboy if you will but I really prefer his game design philosophy over Valve’s. While Half Life 2 was a superbly crafted game it was very linear and more importantly if you got stuck you were screwed until you accidentally figured it out. When you’re stumped for so long you end up feeling stupid; in Deus Ex you could just try something else and it would often work out, thus making you feel smart instead. That’s a good thing.