Well, by the looks of it, almost the entirety of the talk.
Seriously though, are you kidding me? The author of the rebuttal criticises Slavoj principally for not offering alternatives and for not fleshing out his ideas fully. This animation is 10 minutes long. Do you seriously think that Slavoj went to give a talk at the RSA which lasted 10 minutes? Give the man a break. I highly doubt that in his talk, which featured questions from audience members and panelists, he did not address any of these questions at all.
If you want a more precise answer of what the author missed, then I doubt it would be possible to condense this to a ‘smidgen’. This is not a small topic and I suggest that if either you or the author of the rebuttal want a decent idea of Zizek’s ideas regarding society then reading his work would be a better start than watching a 10 minute animated clip.
I learnt that Cologne and Koln are the same city; beat that.