Garbo's Facial Gestures and Usage of Her Arms/Hands

Yes!

Also she looked a lot older than 27.

Greta just the previous year had made her first talkie movie.

So you can see why she was still acting the the silent cinema :)

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In that one way, Grand Hotel reminds me of Metropolis.

In Metropolis, you could see a world in transition: the stage actors used to playing to the balcony, with their exaggerated movements and mime-like facial expressions, and their savvier counterparts who already trusted the camera to pick up subtler techniques. (Not always the young/old division on that you might expect, either.)

And in Grand Hotel, you've got the next-generation version of that: the people who understood that you could now do with the voice what it used to be up to the body and face to accomplish, and those who didn't.

Of course, in both cases there was probably just good old fashioned bad acting next to skilled acting, too. ;)