How bad is it? It aimed high... and fell really, really, really short.
Should you see it? Nah.
When this was made, director/star Sondra Locke was dating producer Clint Eastwood, which is the sole reason this got made, I think. Locke plays a reporter who discovers a rat/human hybrid living in a garbage dump. She then vacillates between trying to help him and exploiting him to further her career. She has some brothers who are just as bad, for comic relief (which fails). As has been pointed out by others, in the colored glasses he wears, the Ratboy looks a little like Bob Dylan! The make-up is by Rick Baker, who tried for cute, but that's not what he does best. The film fails as satire, as social commentary, as fantasy, as suspense, as drama, as melodrama and as farce.