The app must not leave the user stuck at any point in the experience.
For example, if your app requires a login, you must provide instructions for the user to successfully create an account. These instructions must be discoverable in VR, but account creation could happen in 2D.
Game levels must not have broken logic that prevents progressing to the next level.
User must be able to experience all content without being unable to progress or requiring unobtainable information.