I exported the room demo to GearVR and the rotation of the VR cam is always a bit off (on pitch axis), ground is never even for me. Any idea?
Did you use native unity VR integration? In this case just remove SensorRotation component from Head -> Camera, add Camera component and disable 2 child eye cameras. It may be also good idea to call UnityEngine.VR.InputTracking.Recenter(); on calibration (best place to add it is at start of TPoseCalibration.SetHeadAngles() method). Just tested it and it worked fine on GearVR.
I just used the room demo, threw the oculus utitlies into the project and parented a ovrcam to the head (tried parenting to camera aswell). I deactivated all other cameras. I removed SensorRotation but that didnt made it better. Will try recentering.