Superunknown was a breakthrough in many ways.
Not only did the album bring Soundgarden a new audience, it dramatically expanded their vision, as well as their accomplishments.
If Down on the Upside initially seems a retreat from the grand, layered textures of Superunknown, let it sink in.
The sound of Down on the Upside is certainly more immediate, but the band hasn't returned to the monstrous, unfocused wailing of Louder Than Love.
Instead, they've retained their ambitious song structures, neo-psychedelic guitar textures, and winding melodies but haven't dressed them up with detailed production.
Consequently, Down on the Upside is visceral as well as cerebral -- "Rhinosaur" goes for the gut, while "Pretty Noose" is updated, muscular prog rock.
Down on the Upside is a deceptive album -- it might seem like nothing more than heavy metal, but a closer listen reveals that Soundgarden haven't tempered their ambitions at all.