There's not much that can be said about this classic that hasn't been said already. Karloff manages to make a hideous monster touchingly human--anyone who has been on a bad date can empathise with his climatic meeting with his "bride." For me, though, the movies belongs to Thesiger. It's his fey, sibillant mad scentist that makes the film sparkle and rise above its failings: you could make a drinking game out of how many times the actors roll their R's in the stodgy prologue, for example. The biggest failing, though, is Una O'Connor, whose dreadful overacting isn't fit for a London music hall show, let alone a film of this caliber. Why Whale continued to put her in his films will always be unfathomable. Lanchester's man-made woman probably holds the record for biggest impact with briefest screentime award, at least until Boba Fett came along. A quirky masterpiece, and one of the best films of its era.
Note: There was a deleted subplot involving Dwight Frye's character killing off his aunt and uncle for money and putting the blame on the monster. The scenes were cut after the first showings, but production stills survive; this is where those caps are from.