It is impossible to rip off a movie made 18 years later than yours. DNA was made in 1969, Predator was made in 1987. Who was ripping off whom? However, all other comments are undoubtedly valid. Monster movies from this period were notorious for their lack of believability and in many cases the acting and sets were in fact on a par with a bad High School production. 1969 was really an interesting time to make schlock. There was no instant video market like there is now. But there were drive-ins! I saw many bad monster movies at a drive-in where the audience was more forgiving. However, I have to admit I don't remember seeing this particular movie.