There is also a new Alt brewery there, Kuerzer, so I might have to go back someday.You can walk to Uerige, Im Fuschen, Zum Schuessel breweries and the Schneider tap house in the Altstadt in Duesseldorf. Have one at each (.25 liter), then go back to your favorite for more.
Great suggestion - I took a walking beer tour in the Alstadt that did this and it was a lot of fun.
I visited that one on my tour. IIRC it has fermenters that are on the second level and only the very bottom of the cone sticks down through the concrete ceiling. That was the first time I'd seen anything like that.