Data really really helps in analyzing a video. So first stop is to go and get all your data on the video.
Then re-watch the video, comparing how you watch it versus the data you have on its performance.
Stop where people often stop, click where people are clicking. This will help contextualize and understand what the data is telling you.
It may be obvious why people drop off at a certain point.
Then you can go and improve the content, using this data.