The Knife of Dunwall falls into the category of sidestory DLC that expands the story outside of the campaign with the perspective of a different character. In this case the perspective is that of Daud, the assassin responsible for the death of the Empress in Dishonored. A bold move as some of your choices in the main game may or may not have you sympathising with Daud.
For those unfamiliar with Dishonored, it's a first person stealth game set in a steampunk Victorian setting where corruption is at an all-time high among the nobility while the poor frequently become the victims of a horrible plague. Brilliant visuals are accentuated by a painted look, that in part deflects the brutality of some of the deeds you're capable of.
Much like the main character of the main game (Corvo) Daud wears the mark of The Outsider, and when he has taken the life of the Empress, he starts to regret it. Somehow this hit has more disastrous consequences than any murders he previously commited. The Outsider steps in and Daud is led on a journey to discover his part in the downfall of Dunwall. This is the first of a two-part DLC that will conclude with The Brigmore Witches at some undisclosed later point.
For the most part this expansion remains true to the Dishonored experience. There are three chapters complete with exploration, multiple paths, traps, enemies, secrets and rats. One or two tweaks have been made to the gameplay, with Daud not having certain powers such as Devouring Swarm and Wind Blast - but he does have a very handy new ability that allows him to summon a fellow assassin to help defeat enemies or distract them as you sneak by. This ability is brilliant both when you get caught and if you just enjoy looking at your handywork from a distance. The ability can be upgraded to summon more powerful assassins, but you can also upgrade a passive skill that allows these assassins to use certain powers in combat. If you invest your runes in these abilities you will have some very powerful back-up at your disposal.
There are a few new enemy types you'll encounter, including whale butchers with huge buzzing power tools straped to their chests. The Chokedust grenade is another fresh tool at your disposal that incapacitates your enemies allowing you to move in for an easy kill. Daud also has access to arc mines.
The narrative follows the same model as in the main game, but it feels a bit abridged and the fact that the story is split in two doesn't help. Perhaps players should hold off playing this until the second part is release so they can enjoy the full story arc in one go. If you're just playing for the main story highlights and ignore playing stealthily, going for secrets and completing side quests, then you could be done with it in a couple of hours, maybe even less. But if you're going for the complete experience, then reading notes, books and finding non-lethal ways to reach your objectives is going to take a lot longer, especially when playing on harder difficulties. One added feature is the ability of Daud to buy favours - it may be an extra rune placed somewhere in the level or a disabled alarm system - ahead of each mission (no hub similar to Hound Pits Pub, just menus in this one).
As you'd expect there are plenty of interesting characters in The Knife of Dunwall, even if I must say some of them fall a bit short of the level seen in the main game. The environments include two new acquaintances and one you may recollect from the campaign. The first one, a slaughterhouse, featured some further insights into the business of extracting whale oil. Characters are corrupt and evil, or very corrupt and very evil. You won't feel bad ending their lives prematurely.
Overall I must say I appreciate the approach Arkane Studios has taken with this expansion. It tweaks the formula slightly, but doesn't feel like much of downgrade from the main campaign. It expands and adds to the universe already in place, yet it also feels like a vital part of the main story given the involvement of The Outsider and Daud's role in the assassination. It's a little frustrating that we're left waiting for the conclusion, but hopefully it won't be long until The Brigmore Witches sees release.