Highly entertaining. Features a real fight between a lion and a tiger, plus tons of taming action by Clyde Beatty. The not-so-real gorilla, in both her original and semi-humanized form, strangles people. Nice detail: she does it so hard she severs their spinal cords. Interesting premise of hormones used to reshape flesh. (I can’t recall whether this exact mechanism is used in any version of The Island of Dr. Moreau, which is the obvious inspiration.) Speaking of hormones, a disturbing theme of this movie (and its two sequels, both far less fun) seems to be women doing evil by lusting above their class or race.
The best part is John Carradine as the Moreau-like mad scientist. He’s so good I rank him with Marlon Brando as the 1996 version of Moreau; Charles Lawton as the 1932 version in Island of Lost Souls; Ernest Thesiger in The Bride of Frankenstein; and Peter Lorre in Mad Love.