"The show has dragons, who cares if the accents don't match?": Well, first of all, I care. Second of all, the cornerstone of science fiction and fantasy fandom is nitpicking. Third of all, the fact that Game of Thrones doesn't take place within our collectively agreed-upon reality doesn't release it from its responsibility to verisimilitude or the maintenance of internal consistency within its own systems.
The talk itself is great and covers some important stuff. (Of course, it's Feynman!) The key thing here is the connection between theoretical understandings of how the universe works and practical observations. Theories are used to make predictions. When the predictions turn out to be correct, we get some more evidence that the theory is on the right track. Here, Feynman talks about how the theory of gravity led to the discovery of the speed of light, and how knowledge of the effect of gravity on planetary orbits led to the discovery of the planet Neptune. Very cool stuff.
But what stood out to me—and what makes this different from all the old!Feynman videos I've seen—is the persona his younger self projects. Born and raised in Queens, the young Feynman comes across, at least in accent and physical mannerisms, like some big mafia palooka straight out of central casting. Most likely, my startled reaction to this is due to Midwestern bias and being raised in an era where American regional differences in accent and culture have been largely flattened out. But it's still fascinating ... and amusing as hell to hear a guy who looks and sounds like he should be guarding hostages or threatening shop owners instead talking about gravitational theory.