I found this movie amusing for its low budget effects and several flaws in its continuity. The most frequent flaw was the splicing of scenes in which it would appear to be day and then night and back and forth. Despite, or perhaps because of its flaws, I liked it. It does help if you like 1950's "B" sci-fi films and Shostakovich to start with.
In addition to the plot strongly resembling Robert Heinlein's "Puppet Masters", the music was also not original. I could find no evidence that there ever was a "Tom Jonson" who wrote any music for this film or anywhere, ever. Most of it was taken, uncredited, from Dmitri Shostakovich's symphonies 1, 5, & 10. I also recognized an excerpt from Sergei Prokofiev's music score for the Russian language film Alexander Nevsky. At the time Brain Eaters was distributed these composers were not as frequently performed in the US and their music would not have been familiar to almost all movie goers. Both composers were from the Soviet Union (Prokofiev died in 1953). They were perceived as Communist and there was a certain amount of prejudice and/or fear about performing it. During the cold war it would also have been difficult for Shostakovich to pursue legal action against the film company if he even knew his music had been used. I suspect this is exactly why this music was used.
I also would not be surprised if it turns out that the source of the performances were records purchased at a record store and the musicians were not compensated either. The credits do not list any orchestra(s)/conductor(s). The editing of the background music was also poorly done. There were several places where the music did not transition smoothly to the next scene or even within the same scene.
