Generally positively received, it includes some of their notable songs, such as "Disasterpiece", "The Heretic Anthem", "People = Shit" and the Grammy-nominated "Left Behind" and "My Plague".

It was accompanied by full live audio of the hit DVD Disasterpieces and a film entitled Goat directed by Shawn Crahan, with the four music videos, never-seen-before interviews and footage from the Iowa period.

[8] Drummer Joey Jordison and bassist Paul Gray began working on new music together in October 2000, and wrote material for most of the album.

[10] During an interview with Guitar magazine in November 2001, Root explained, "It was so exciting as well as scary to be part of this whole huge process," adding that there was a lot of pressure from fellow guitarist Mick Thomson to perform well.

[15] While recording vocals for the closing title track, he was completely naked, vomiting all over himself, and cutting himself with broken glass.

"[15] While producing the album, Ross Robinson was injured in a dirt bike accident, suffering a fractured back in the process.

He returned to the studio after a day of hospital treatment, reportedly "putting all of his pain into the album", much to the admiration of the band.

"[18] Iowa, unlike its predecessor, saw Robinson capturing the band's technicality as opposed to the raw energy which Slipknot became known for.

NME stated that "every possible space is covered in scrawl and cymbals: guitars, percussion, electronic squall, subhuman screaming.

"[19] Iowa has also been critically acclaimed as one of the only mainstream musical albums to feature blast beat percussion, and was said to heighten its popularity after release.

[20] Although Iowa became widely regarded as the band's heaviest album to date, some tracks incorporate melody, most apparent in the record’s singles such as "My Plague" and "Left Behind".

They compared several songs, namely "Disasterpiece," "People = Shit" and "The Heretic Anthem" as more death metal-influenced than most of the nu metal that the album contained.

[19][23] The album also includes many expletives; David Fricke of the Rolling Stone magazine said "there isn't much shock value left in the words fuck and shit, which Taylor uses in some variation more than forty times in Iowa's sixty-six minutes.

"[23] Fricke went on to praise Taylor's performance on the track "Iowa", comparing it to a "vivid evocation of a makeshift-cornfield grave at midnight.

Members have claimed that Iowa was the source of their energy, and they consciously made the decision to stay in the area, partially due to the fear of losing their creative direction.

[8] The opening track "(515)" is also a reference to their home state, named after the telephone area code for central Iowa.

[34] Following the success of the band's self-titled album, author Dick Porter wrote that the anticipation for a follow-up was intense.

[35] The College Music Journal reviewed it as "brutal, unrelenting, scorching..."[44] Many noted its heavy themes: Alternative Press stated, "[It is] like having a plastic bag taped over your head for an hour while Satan uses your scrotum as a speedbag....[It] is over the top… you're going to be left in stitches.

"[46] Rolling Stone credited the album for its originality, stating that "nearly everything else in modern doom rock sounds banal.

"[49] Reviewing for Yahoo!, John Mulvey said, "They're an evolutionary dead end, the final, absolute triumph of nu metal.

[65] All music written by Shawn Crahan, Paul Gray, Joey Jordison, Chris Fehn, Mick Thomson, Sid Wilson, Craig Jones and Jim Root except where noted.