The goal is to produce a subtly different take on the first person perspective. Normal wasd-mouse/left stick-right stick controls are still used. Direct control is over the body (wasd) and direction of sight (mouse), which means as you will see is more than just directly rotating a camera. In the following video, 98% involves no wasd/left stick movement, the “leaning” or " looking around" effect is automatic, dynamic and the inherent fundamental difference to the usual first person perspective view.
The main difference is that you are directly moving the eyes and the head automatically follows your eyes with the eyes also having and amount of calculated control to keep them facing the direction of sight. The head then moves to match the eyes direction of sight. This is different because if you notice in real life if you rotate your head the to the left. The eye is a child of the head so moves in an arc physically in 3D space. Try it yourself. You sit stationary looking at your screen. Somebody walks by you to your left. You glance at this person for a moment so the position of the eye is still the same (the rotation has changed) but then if you look at the person, your head rotates and as a consequence of your eye being attached to your head, the position of your eye changes not just the rotation. Your eye then naturally rotates back to the direction of your body. Keeping your head still move your eyes to rotate back to the screen. You can now actually see behind the left part of the screen. In the video, there is no extra leaning going on, it is the natural effect of the view changing because of the head and eye positions.
At the moment there is a slight amount of drift. It’s not supposed to be there and will be eliminated during development. Further updates posting to Twitter @astonishedbd and http://www.astonishedbydesign.com