the organ
Love Phibes' organ. It is cool - with a nice red acrylic Art Deco-ish design around the playing unit (keyboards, bass pedals and tone controls) - but it makes no sense whatsoever to someone knowing about the subject (it is part of my profession being a musician/pianist/Hammond organist).
The U-shaped rows of tonetabs (tongue shaped) make it look exactly like a 1910s/20s US (!) theatre organ (Wurlitzer style). But what we hear at the beginning is an epic, gigantic, all stops out "Volles Werk" sound, most likely that of a full sized church organ (there must be a 1000 square feet room behind the playing unit that holds all those pipes and mechanics). Later into the movie we clearly hear the recording of the more mellow tones of a Hammond organ, complete with rotating Leslie speaker cabinet - both not introduced until the 1930s.
Also: the organ can move up and down like an elevator, I am pretty sure that this would be next to impossible to do unless employing 21st Century digital technology.
Love the built-in telephone though! (Vulavia, bring me a glass of water, wouldya please, playing Bach always makes me thirsty).
I fully understand the choice of design and sounds - it's not meant to be technically accurate - but I thought I'd add my ramblings anyway.
P.S. please don't get me started on the movements of the hands.... ouch!