Unlike many other games, this one was built ground up for a head mounted display instead of adapted for it. As such the user interface and control scheme are well optimised for the Oculus Rift.
All interaction in the game are done using the headset. Head gestures are used to interact with the user interface and aiming is done by looking at the target.
The game creates a frame of reference for the player by having his avatar be stationary. That helps avoid motion sickness commonly induced by the dissociative feeling created when the avatar is moving and the player himself is stationary.