In Dishonored, the first power granted you by the Outsider—the only one which you have no choice over—is the short distance teleport ability, Blink.
What Blink offers is more than simply the ability to instantaneously move forward. If that was the extent of its power it would still be useful but it wouldn’t be as disruptive as it is. Rather than being restricted to directly ahead, the destination of your Blink can be anywhere within a sphere around your current location: the roof of a building, the floor behind an NPC, or the middle of the air. Provided there is a straight line between your current position and the destination, you can Blink there.
The elegance of Blink comes from the few restrictions placed upon its use. It is not context dependant; there are no specific “Blink-able” locations. It can be used to move through any space that you could normally occupy, so you cannot move through solid surfaces or active Walls of Light. Finally, it uses the same amount of Mana as is automatically replenished, making it readily available. With so few restrictions, the decision of when, where, and even if, to use Blink is left up to the player.
Instantaneous movement between two points on the same horizontal plane is useful; the effect Blink has on your perception of, and engagement with, vertical space is where it becomes truly transformative.
By not being limited to the horizontal, Blink changes the usable topography of a level. Normally in a first person game it is possible to jump onto higher surfaces and in so doing alter your vertical position. Given a standard model of gravity the path to these higher spaces is slower than the path down, though it is also much safer. From a high point you can leap off and will likely take damage when you land. With Blink you can teleport up to a roof and back down with the same expenditure of time and Mana. You can move as rapidly and safely in the vertical dimension as the horizontal one.
The Knife of Dunwall DLC changes the core Blink ability, further enhancing its strength as a tool for vertical movement. When initiated time will freeze provided you are not manually moving in any direction. This means you can fall from a great height and at the last moment initiate a Blink and have as much time as necessary to target a safe landing spot. The reverse is also possible; you can perform a Blink at the top of a jump and use it to reach even greater heights.
One of the constants of first person games is movement through space, by providing you with a power that allows for near instant movement between two points in any dimension Dishonored disrupts the standard model of movement and succeeds in making vertical movement almost as safe and rapid as horizontal movement, changing the way players perceive and interact with the space around them.