Early Dishonored review scores show that this game is definitely one of the most anticipated games of 2012, developed by Arkane Studios and shown across various game conventions and with many trailers to follow it the game has already earned a solid 9.5 from CVG (you can see their review Here)
While some gamers have been reported to beat the game in only a matter of 4 hours but it is obvious that these are simple speed runs of the game as with most games on launch. The game will easily take 20+ hours if you take your time and want the fullest enjoyment, much like Deus Ex: Human Revolution.
Dishonored is one of this years hottest titles, following the footsteps of Deus Ex: Human Revolution and many other games before it the game can be tailored to your play style, you can be loud and reckless and get the job done by going guns blazing like a scene from a Matrix movie or you can choose the more preferred and efficiently stealthy approach especially if you plan on taking on the achievements / trophies in this game.
The source also mentions that those who got the early copies of Dishonored were able to beat the game in only 4 hours, this is possible if they only speed ran through all the game and completely missing out the good parts of it.
A speed run for games like Dishonored is simply awful and undesirable, if you don't have the patience to put in 20 hours of your time for what appears to be a very enjoyable RPG then you can simply vouch for the 4 hour route and not get the full value of your purchase.
Even the level designer (Dan Todd) took 22 hours to beat the game without getting any kills or raising any alarms and this guy was supposed to know every twist and turn of every stage: (taken from the source and originally said Here).
“My ghost and no kills playthrough took 22 hours. That’s without exploring every nook and cranny, and knowing the solution to everything beforehand.”
Don't let the speedrunners fool you, this game will have a lot of replay value and you will easily do more than one playthrough of it to experiment with different play styles or simply to enjoy the story from a different perspective.
Dishonored will officially launch on October 12th for the PS3 , XBOX 360 and PC.
UPDATE: It seems I have been getting emails and comments asking if the 4 hour playtime is valid and while I can't find who it was I found this thread on NeoGaf forums and would like to direct your attention to this post in particular
The following is taken from the latter link.
I'm a little worried about this game. Someone got a copy early from one of those mom and pop type stores and they beat the game in around 4 hours on easy. They streamed it but I didn't witness any of it. Just what I heard from the grapevine. Hope I'm wrong.
That's been discussed for like the past day here lol. Apparently guy just played it on easy and killed everything and did no side quests.
As you can see the 4 hour target is not completely impossible and despite not having a proper name there is at least some proof of the existence of said run.