The reticle/cursor is mapped to user head movement. To trigger an action, simply point the cursor at a button and dwell.
To allow for easy button targeting with minimal head movement, "friction" was added to the buttons. This meant we could tune the cursor to have higher velocity when not over a button, which translated into less head movement.
We prototyped a few variations of the cursor orientation. The first was having the cursor/reticle fixed to the center of the screen. When the user moved their head, the content would move in and out of frame. The experience was intuitive, however this created an issue on screens that had text, making it more difficult to read.
We settled on a dynamic cursor/reticle, similar to a mouse. This meant that content was always fixed on screen, and easy to read, regardless of how much the user was moving their head.