Would audiences in 1938 have noticed...
... that the Earthmen can pilot/handle any piece of technological equipment even though they'd never seen it before? And they're better at opening/closing doors than the natives: when Flash 'locks' the guards up by closing 2 doors, the guards just keep bumping into the flimsy door instead of turning the wheel just next to it; they reminded me of Lemmings(TM).
I watched this serial for the first time and it's quite fun and rather silly (turning the wheel to close the doors made me laugh out loud), but these 2 nitpicks annoyed me enough to not really get into the serial after that, it all seemed just too silly.
Am I too logical and would audiences 70 years ago just accepted these things? After all it's SF with rays, light bridges, incredibly useless bombers, ... stuff that any all-American quarterback can handle ;)
Maybe I should just switch off my brain and enjoy it for what it is: silly but enjoyable SF fluff.