Somewhere deep beneath all the implausible nonsense & preposterous ideas, there's a solid and intriguing plot hidden in "The Invisible Man Vs. The Human Fly". The story revolves around a vicious night club owner/war veteran who takes revenge on his former associates via shrinking his henchman with a serum until he has the size of an ordinary housefly. The fly then kills his enemies without leaving a trace - apart from an audible buzzing sound - and the media assumes there's a murderous invisible man at large. Now, the clever part of the plot is that the henchman is a psychopath addicted to the fly-serum, and he also starts killing random people that he has issues with, and this severely complicates the police investigation. Oh, and there's also an actual invisible wandering around, otherwise the title doesn't make sense.

Watchable (and even slightly better) sequel to "The Invisible Man Appears" (1949) but still a long way from qualifying as classic Sci-Fi or horror. Around the same time in the US, Vincent Price was starring in "The Fly" and "Return of the Fly", and those movies are a lot better and more entertaining. Certain special effects, like the floating head or the reduction process, are very good but others - notably the little guy flying and buzzing - are ridiculous. Besides, why does he buzz when he's still shaped like a man?

The film also has too many supportive characters and confusing sub plots, and there are loads of irrelevant and pointless pieces of dialogue. For instance, at three different times, there are a bunch of people discussing whether it wouldn't be more accurate if they refer to the invisible man as "the imperceptible man". What? Whatever...