The author account describes building a playable mobile AR experience and reaching TestFlight. Camera, gyroscope and rendering behavior had to work together on a device.
Use the first playable loop as a checkpoint: find a ghost, interact, receive feedback and repeat. Device motion, performance and production builds need their own checks after the scene looks convincing.
What this does not establish
The source describes differences between development and production behavior. Timing and success are author/vendor reports, not a recipe we have reproduced.
