As with the official theory test, most clips only have one score-able hazard. However, a small proportion of clips have two hazards. There may well be other hazards in the clip beyond the one or two that are scored. Although identifying these will not score any additional points, clicking when you see them will better prepare you for the real hazard perception test.
For more information on scoring, please watch the tutorial video by clicking on the Hazard Perception tab in your account.