Ahh, pre Hays Code horror movies. There's a certain charm to the sort of ghoulish thrills they could include before the censorship guidelines of the day were introduced, but the kind that are still within the accepted limits of this period of cinema. Nothing exemplifies this quite as much as the James Whale adaptation of H.G. Wells' story. The death toll is surprisingly high as Dr. Griffin runs amok, though there is never any real violence on screen. Of course this is all done with a dark and twisted sense of humour as he rants and raves about revenge and his lust for power and calls people miserable fools every few minutes. There are many classic entries in the Universal series, but this is best; it may portray a human title character, but he's certainly the most monstrous.
Claude Rains is what makes this all so entertaining, so it's surprising that it was intended to be another Boris Karloff feature. While I'm curious to know what that would have been like, it's impossible to imagine a performance better than the version we have. His maniacal laughter, constant belittling threats and his obsession with making people suffer under his whims create a character far more threatening than anything else from this decade. Even normal conversations quickly turn into megalomaniacal speeches, and his sadistic side is frequently brought out by minor events. His payback on fellow chemist Kemp stands out in particular, not because of the act itself but the dialogue as he builds up to it. The combination of twisted lines and fabulous voice acting are a major reason this all works.
Obviously there are certain effects sequences that add to this, and a lot of it is still impressive now. There are a few objects moving on wires that are never convincing, but certain invisibility shots and matte effects work really well. The first reveal as Griffin takes off his glasses and nose, and later when he's unwrapping the classic bandages in front of a mirror are really eye grabbing even if it's just for a few seconds. Modern transfers show up all the rough edges just about everywhere else, but ultimately it's not a problem. Once he stars to wreak havoc on the locals it's impossible to complain.
As a tale of meddling with science and experiments gone awry it holds up as a suspense story and as a mixture of action and horror. It may lack the sort of atmosphere from Whale's own Frankenstein in some ways, but this is a different take on the idea. They still include plenty of oddball side characters to keep things interesting, from the police actors to the owners of the inn which begins the story. It does feel a little out of place that there's a love interest in all this - particularly when there's so much death and mayhem. The title character is just a total lunatic for most of the film, so it feels a little forced when he has to have trite romantic scenes. But this is a minor complaint in the grand scheme of things. For its time this does what it set out to with stellar results, and while other sci-fi and horror creatures have gone on to become more iconic, this is still the major high point for the '30s.