it not exactly a major shock that boris karloff play a mad scientist in this film and though it be very unusual the way he play this role . instead of the evil twisted genius set on make monster or rule the world and karloff goal be incredibly noble . and and when he later kill and you really understand with and could possibly condone why he do this . the moral implication of the film be astound . a for the rest of the film and the writing for this sort of b movie be very good and the acting fine and production value work out well ( prove you do not need a huge budget to make a good film ) . about the only negative at all be the end ( i would have just end the film a minute or two early without the unnecessary final scene ) and a mistake in the film about how deep the lab be under the earth . in the beginning and they count 191 step to the bottom of the shaft to the lab and but later and it just a homemade ladder about 12 foot long . regardless and it do not harm the film in any serious way and the film be a very good amad scientist flick that actually be good entertainment and well think out .