This is, as far as I can tell, the oldest piece of horror cinema in existence. At just over twelve minutes, it offers a greatest-hits abridgment of Mary Shelley's novel along with some new elements that place the emphasis on psychological horror rather than sewn-together body parts. There are some other alterations as well. Specifically:
The monster's creation scene, which has become fixed in popular culture based on what happened in 1931's Frankenstein, is here way more witchy. There are no pallets rising to meet the lightning, no spark gaps to shock Bela Lugosi. Instead, we get a monster ascending from a cauldron, first as a waving skeleton, then affixed with layers of bulky flesh. It's a kewl image.
Sort of like Demons, innit? The finished creature is quite bulky and husky, but probably not as imposing and iconic as Karloff's definitive rendering. As it menaces its creator, we see the film's main artifice, a mirror gimmick that suggests the psychological horror that I mentioned up there in that other paragraph.
Wise readers can probably guess what is suggested by these shots and they definitely mesh with this film's tweaked ending, which is pretty cool if you are not a Shelley puritan. Given that its the silent era, one expects overwrought acting with arms flung emotionally about. And you get some of that, but not as much as you might think—maybe the "sawing the air" style of hyperemoting evolved as actors competed with one another? Maybe it wasn't born complete out of a pot, like Frankenstein's monster? IDK.
Visually, this is solidly stuck in olden times. Even given its brief duration, you'll probably get antsy over the constant static wide-angle shots. The set decorations also seem to recall past eras, much more in line with a theatrical production than what we'd expect from a modern movie. Even so, this is where it all began and it's well worth the time it requires for viewing. And you can watch it for free, just below the stars!