The band were disappointed with the relative lack of success of the album's singles and went on "pop strike" as a result, issuing the 'lo-fi', all-Welsh language Mwng as the follow-up to Guerrilla in May 2000.

[3][4] The Super Furry Animals had originally intended to work on the album with Gorwel Owen, who co-produced 1996's Fuzzy Logic and 1997's Radiator with the band.

[3] Although Rhys has stated that the group met Gabriel several times during recording, and that they thought he was "a good old guy", Real World was chosen because it was near to the band's homes in Wales rather than because of its association with the former Genesis frontman.

[8] "Do or Die", "Fire in My Heart" and "Keep the Cosmic Trigger Happy" were written by Rhys while "The Door to This House Remains Open" developed from a band jam of the Rod Stewart song "Do Ya Think I'm Sexy?"

[3] The band chose to sequence the album like a hip hop record, with "Check It Out" as an introduction and "A Specific Ocean" and "The Sound of Life Today" as interludes.

[9] The band added the subtitle "Non violent direct action" to the album's packaging to ensure that no-one could read any "crass, militaristic statements" into the name of the record.

[15] The NME featured an interview with the Super Furry Animals, several weeks before the release of the album in the United Kingdom, as the lead article in an issue which discussed the "nu-psychedelia" musical genre, which they saw Guerrilla as exemplifying.

[2] The singer has also said that the album is not a radical departure for the group musically, although it is "more groovy and uptempo [...] more textured and punchy" than the band's previous releases, partly due to the mix which creates a "more American sound".

[19] Select stated that the album juxtaposes pop songs with "rambling odities" and is dominated by the "electronic throbs and pulses" of keyboard player Cian Ciaran at the expense of guitarist Huw Bunford.

[12] The magazine went on to state that the song sums up the album due to its "defacement of symmetry" and disorder, which is also evident on "Do or Die", "The Turning Tide" and "The Teacher", all of which start as pop before ending up "skew-whiff under a wealth of hooligan noise".

Critics have described the song as a techno track, with Pitchfork calling it "floor-slapping LSD-infused electronica" and Spin stating that it is "a psycho ward of tweaked noises", reminiscent of the music of Daft Punk.

[8] Critics have commented on the song's use of "Tijuana brass", reminiscent of the work of Herb Alpert, and likened the track to the music of Burt Bacharach and Hal David and the Beck single "Deadweight".

[8] Guerrilla was released on 14 June 1999 in the United Kingdom on CD, cassette, Minidisc and vinyl by Creation Records and peaked at number 10 in the UK Albums Chart.

In a departure from the illustrations he had provided for the Radiator campaign, Fowler worked in 3D, creating a model of a yellow monster dubbed the "God of Communications", smoking a pipe and wearing a "mobile phone and bandolier belt".

[26] Guitarist Huw Bunford has stated that the band originally intended to hide the track in the album cover itself, by way of a special vinyl sleeve design, but the group's record label, Creation, refused to allow this due to the cost.

Mojo called the album "magical stuff" and commended the band for their ability to mix musical styles, being particularly impressed with the juxtaposition of the esoteric "Wherever I Lay My Phone (That's My Home)" and the "trad-sounding" "Fire in My Heart".

[15] Cokemachineglow also commented on the band's musical versatility, stating that, although the record features a mix of styles, it is a cohesive whole; a "perfectly flowing album", that showcases some of the Super Furry Animals' best songs.

[37] The NME called the album "an acid fried quadrophonic vision of rock 'n' roll" and suggested that it was a masterpiece which could define the era in which it was released, in the same way that Primal Scream's Screamadelica did in 1991 and (What's the Story) Morning Glory?

[12] Select placed Guerrilla at number nine in their albums of the year award for 1999 and called "Somethings Come From Nothing" the record's highlight, stating that the track "oozes an epic, sonourous electronic sadness around Gruff's muted mumbling of a single sentence".

[20][39] Despite dismissing "Wherever I Lay My Phone (That's My Home)" as a throwaway novelty song, the magazine stated that Guerrilla "makes experiment engaging" and concluded that it was a "brilliantly subversive" attack on the charts.

[19] British newspaper The Independent stated that, although the record includes a number of exceptional tracks, it also features a "lot of noodling" and claimed that it does not compare favourably with the work of The Flaming Lips.

The magazine did, however, feel that the record's disparate influences were too often "left hanging like loose wires" and that there was an air of forced eccentricity about the release, despite praising lead single "Northern Lites".

[22] Super Furry Animals embarked on a brief, five-date, tour of the United Kingdom, in support of first single "Northern Lites", beginning at Tenby De Valance Pavilion on 27 April 1999 and ending at the Cambridge Corn Exchange on 2 May.

[47][48] The band undertook a tour of the United States and Canada, beginning at Maxwell's, Hoboken, New Jersey on 14 September and ending at the Coachella Festival on 9 October.

Singer Gruff Rhys wrote a tour diary, covering the first nine dates from 14–26 September, which appeared in the 9 October 1999 issue of the Melody Maker under the title "Guerrillas in the Midwest".

[2][49] The group played a fifteen date tour of the United Kingdom, starting on 15 October at the Royal Court Theatre, Liverpool and ending at the Brixton Academy, London on 3 November.

[6][34] The band were disappointed with the relative lack of success of the album and its singles—none of which managed to chart inside the Top Ten of the UK Singles Chart—and went on "pop strike" as a result.