Making two videos, full and summarized, might take a lot of work. If anything, making a list of potential negatives and positives at the end could be a way to resolve that. It's safe to assume people know how to skip through to the end where you list and rate, right?
Also, gameplay footage is sufficient. Unless it's your aspiration to become a professional reviewer, even picture-in-picture isn't widely used by professional video game reviewers. Only show I remembered doing picture-in-picture was early Electric Playground, and I'd rather watch the gameplay.