I seriously doubt a history lesson in 15 minutes that covered WWII to Vietnam is meant to be comprehensive. With that said, when I was in school we regularly covered a thousand years in a single page. And in many cases complete eras as pertained to geography were skipped altogether. To this day I don't think I could tell you the name of a single African King pre-1900.

With that said, one of the things I still prefer about Khan's lectures, even abbreviated ones like these stated, is that I can pause them at any time, and look up the Japanese oil embargo. And start right back up where I left off in the video. With live lectures at best you can take a note of it, and look it up later, but then other facts that build upon this in the lecture are missed -- and you may not even know that you missed them.