I beat Deus Ex: Human Revolution for the first time last night. "The first time," because I immediately started replaying it on the highest difficulty level. It is that good.
The first way through, I was still mastering the game, which is my first stealth game. One of the beauties of DE3 is that you don't have to play it as a stealth game. It plays perfectly well as a MASS EFFECT-style crouch-and-shoot game. But for me it's a lot more fun sneaking around and knocking out enemies without being seen.
(And I feel better, too. I don't like killing security guards just because they're working for an evil corporation. Don't
mooks have families too?)
(Oh, and you get lots of XP for Not Being Seen. And if you can get through the whole game without killing anyone, you get an Achievement. So I sort of feel the game is meant to be played that way. Hunter, however, prefers shooting mooks in the head with his silenced pistol. To each his own.)
One reason Deus Ex is such a lovely game is there are multiple ways to do missions. To get into that room, you might be able to sneak past the guards if you time it right. Or, discover the vent that takes you past them. Or, stack boxes so you can get over the fence on the other side. Or, get that enhancement that turns you momentarily invisible.
Another reason is there are consequences. At the beginning of the game, you're told there's been a break-in at a manufacturing facility; you're needed to resolve the situation before Detroit SWAT charges in. In most games, that situation will wait while you explore the world, do side-quests, etc. In DE3, you have 15 minutes to get on the helicopter. After that, there's no mission. The hostages are dead and your boss is not happy with you. Needless to say this adds a great deal to a feeling of verisimilitude
Another reason is that dialogue is gameplay. In most games, dialogue is only part of story. There may be dialogue options, but no matter what you say, if you need information, you can keep clicking on the Non Player Character until you get all of it. In DE3, you can talk your way past a guard, or you can fail to, in which case you may have to go through the sewer.
Clausewitz said "war is a continuation of diplomacy by other means." In DE3,
dialogue is a continuation of combat by other means.
All of this takes a great deal of work in development and production. The story has to make sense whether you save the hostages or not. It takes much longer to playtest scenarios in which the hero can shoot, sneak, jump or talk his way somewhere. Kudos to Lead Game Writer Mary DeMarle for her awesome work, and to Eidos for giving her the authority to do it right.
But everything about the game is first class. Programming (I've only run across two glitches), rendering, the richness and density of the world... I think I'll hang out here for another little while.