There are a lot of very underrated sci-fi/fantasy-based films from around that time... Actually, I think there are a lot of very underrated sci-fi/fantasy-based films pretty much all the time. Even though some things get lucky and make it big (Star Trek, Star Wars, etc.), the genre as a whole is sort of a weird, insular little subculture, and a lot of great stuff gets overlooked by the mainstream. Although I think we're beginning to see some changes in that...