I think that original 's' was a good start, only it looked too much contructed. The upstroke could be more slanted. Imagine how it looks in upright fonts — it usually is not "upright" as well, but already slanted — so I think it looks more genuine if the italic version is slanted more than the italic stems. It could also be slightly curved.
By the way, I think the upstroke connecting the s strikes as too thin (compared to the thinnest in 'd', for instance).
Interestingly, the German Wiki shows a different version of that alphabet than the other ones. That might imply something about the alphabet's real life popularity. As much as I enjoy learning German, I'm only a beginner. Andreas, maybe you could shed some light?
The ampersand is rather lovely! About the video: I'm kind of disappointed. I was expecting something more exciting—but maybe that's because and idea of a typographic music video or something has been haunting me recently.