The internet is rife with layman's explanations of some complicated things. Understanding something is great. It is also great to get a bath in the real complexity - occasionally.
This is one. The search is on to find how it is the four forces, gravity, E&M, strong force( quarks) and the weak force have the strengths they do. String theory seems not to be advancing, some say, and this talk goes back to the Kalusa Klein model that introduced only one extra dimension back in 1921.
The speaker develops this theory with the express purpose of discovering what accelerator search strategies at the LHC might yield data supporting the 3+1 model.
While in school I sat through lectures that I understood no part of. These lectures were, in some ways, a more important experience than were the ones I understood. Generally, however, I did not have the inclination to listen to these again.
The present speaker is exceptional. One gets the feeling hearing it again might be a good idea.