Wow, that was amazing. The man is a genius, there's no other way around it.
The guy playing Paul was just a lost cause, the girl singing Susan forgot that this was a comedy number--all the jokes fell flat, Amy was much better though, the only one I thought had potential. But Sondheim stole the show, not only does he understand his music/lyrics but he understands theater, the staging, the audience. Amazing.
The other clips are just as good. The guy who tries singing "Later" is terrible but seeing Sondheim talk about the song and the character and basically act the number himself is orgasmic.
"Some people can thrive and bloom living life in a living room, that's perfect for some people of one hundred and five. But I at least gotta try, when I think of all the sights that I gotta see, all the places I gotta play, all the things that I gotta be at"