Beystiman It's fun, it's light, [but] it has a hard time when its tries to get heavy.

Invaderbank The film creates a perfect balance between action and depth of basic needs, in the midst of an infertile atmosphere.

Fleur Actress is magnificent and exudes a hypnotic screen presence in this affecting drama.

Scarlet The film never slows down or bores, plunging from one harrowing sequence to the next.

bnwfilmbuff Mad scientist Tetsu Nakamura has a couple of failed experiments on his brother and wife turning them into mutants while studying evolution. Conveniently, journalist Peter Dyneley stops up to his cabin laboratory hidden on top of a volcano to do an interview and the "good" doctor seizes on the opportunity to try again. After drugging him, Nakamura injects him with the experimental serum and then uses his ravishing assistant Terri Zimmern to lead Dyneley astray into a life of drunken binges and Geisha girls giving the serum time to take effect. Dyneley eventually evolves into a murderous two-headed Neanderthal. Only worth viewing for its camp value.

BA_Harrison Mad Japanese scientist Dr. Robert Suzuki (Tetsu Nakamura) hopes to create a serum that will advance human evolution, but all efforts so far have been less than successful, earlier attempts having turned his wife and brother (who apparently volunteered for the experiment, making them just as mad as he is) into hideously deformed monsters.Not one to admit defeat, Suzuki—aided by his glamorous assistant Tara (Terri Zimmern)—gives it one last go, drugging and injecting roving US reporter Larry Stanford (Peter Dyneley) without his knowledge. The serum takes effect gradually, Larry becoming progressively more wild and uncontrollable, first succumbing to the pleasures of booze and geisha girls, but eventually turning to murder. As his personality becomes more monstrous, so does his appearance: his hand gets hairy, an eyeball appears in his shoulder, and he grows a second head, eventually splitting into two separate beings.A wonderfully subversive storyline and a standout central performance from Dyneley help distinguish The Manster from most of its contemporaries; Stanford's insatiable sexual appetite and violent outbursts, Tara's dubious past (I'm guessing that she used to be a hooker), Dr. Suzuki's callous and calculating approach to his 'work', and the unforgettably surreal transformation from man to beast all go to make this film a genuinely freaky and thoroughly enjoyable ride into darker-than-usual 50s B-movie monster territory.7.5/10, rounded up to 8 for IMDb.

LeonLouisRicci A lusciously lurid monster movie that takes the "split" personality genre to its logical conclusion. An American/Japanese ultra low budget production that delivers the goods with excessive amounts of sex, violence and atmospheric sets that betray its limits.Young movie goers today will probably find much to giggle about but undoubtedly some of the laughter will be of a defensive nature. Because there is truly some disturbing images and subversive things going on here.The mad lab scenes are impressively expressionistic and effective as are the monstrosities created by the nutty professor. There are many silly films of this nature in that era from quick buck makers. This is not one of them. A surreal treat, overlooked, and under-appreciated.

Paul Andrews The Manster is set in Japan where an American named Larry Stanford (Peter Dyneley) works as a foreign news correspondent, Stanford is invited to interview a Japanese scientist named Dr. Robert Suzuki (Tetsu Nakamura) in his mountain top laboratory. While there Suzuki drugs Stanford's drink & injects him with an experimental serum he has been working on, at first Larry seems fine but soon changes as he becomes aggressive, hateful & rather unpleasant. Stanford begins an affair with Suzuki's female assistant Tara (Terri Zimmern) but this part of Suzuki's plan to keep an eye on him, soon Stanford begins to change psychically as well as mentally with an eyeball appearing to grow out of his shoulder which eventually grow's into another full size head. As a two headed freak Stanford goes on a killing spree but realises that his only hope is to go back to Suzuki & try to get him to reverse the horrifying transformation...This American & Japanese co-production was directed by George P. Breakston (also credited as producer) & Kenneth C. Crane (also credited as editor) who manage to turn in a pretty decent little mad scientist monster film that is far better than many similar efforts from the same period. It has to be said that the two headed monster/man genre hasn't fared too well, the only two other examples I can think of are the much derided pair The Incredible Two-Headed Transplant (1971) & The Thing with Two Heads (1972) both of which are extremely silly films so it's somewhat of a surprise that The Manster manages to pull off the two headed monster plot with a degree of respectability. For it relatively brief 72 minute duration (brief when compared to some of today's two & a half hour marathon's anyway) The Manster is pretty effective, it's a strange film for the period as although it deals with horrible experiments which lead to a monster that kills people the script has an entire cultural subtext as it follows an American in Japan & there are plenty of way the script can be interpreted with Japan & it's culture 'infecting' Stanford & the scene at the end in which the brutish part of him that is brought out by the serum detaches itself & is destroyed (along with his Japanese lover) after which Stanford returns to 'normal' could be considered a racist attempt at making a point that Japan is evil & the aspects of it & it's culture infected Stanford & his salvation at the end is when this Japanese part of him is weeded out & destroyed. Or then again maybe I am just thinking about it too much. It's just that the script tries to suggest that Stanford isn't himself & that there's something wrong with him for shunning his wife & traditional American values, well that's the feel I get from it rightly or wrongly.The Manster moves along at a decent pace, it takes itself pretty seriously & is fair entertainment. The Manster in feel & tone is closer to a Dr. Jekyll & Mr. Hyde split personality story rather than a two-headed monster film & you sort of sense the makers had lofty ambitions. There are some good scenes here with the infamous eyeball in the shoulder a particular stand-out & even the two-headed monster at the end looks alright although the hairy beast thing looks rubbish & there's also a disfigured woman that Suzuki keeps locked up. Talking of Suzuki it's never really explained what he hopes to achieve by the experiments he conducts or why Larry Stanford is such a perfect specimen, none of his experiments seem to mean anything. The opening titles feature a goof as the credits misspell the word original during the 'from an original story by' credit.Actually filmed in Japan which is unusual for an American production at the time, shot in black and white the film looks fine & while it has dated a bit it's still watchable enough. The acting is alright, no-one is terrible but no-one is brilliant either.The Manster is a pretty good late 50's black and white sci-fi horror film that tries to make a point about culture, adultery & controlling the evil inside us that is actually more fun when it's a straight monster film rather than a soap opera styled moral drama. Not bad at all & worth checking out.