The first eight tracks are the only material recorded by the Adolescents' original lineup, which included guitarist John O'Donovan and drummer Peter Pan.

[1] The Adolescents had formed in January 1980 with an initial lineup of singer Tony Brandenburg (credited on The Complete Demos by the stage name Tony Reflex), bassist Steve Soto, guitarists Frank Agnew and John O'Donovan, and a drummer who used the stage name Peter Pan.

[2][3][4] The first four tracks on The Complete Demos— "We Can't Change the World", "Black Sheep", "Growing Up Today", and "We Rule and You Don't"—comprise the band's first demo tape, recorded March 14, 1980 in Brandenburg's mother's garage in Anaheim, California using a Toshiba Reflexon cassette deck, and were never re-recorded for later releases.

[5] The next four tracks—"I Hate Children", "No Friends", "Who Is Who", and "Wrecking Crew"—comprise the band's second demo tape, recorded in May 1980 at Phantom Studios in Midway City, California with audio engineer Richard Freund.

[2][3][4][7][8] Encouraged by having their May 1980 demo tape played on the radio by KROQ-FM disc jockey Rodney Bingenheimer on his "Rodney on the ROQ" program, the new lineup recorded a third demo tape that July at the Casbah in Fullerton, California, with Chaz Ramirez and Eddie Joseph of local band Eddie and the Subtitles engineering the session.

[3] The fourteenth track on The Complete Demos, "Richard Hung Himself", was recorded during this session and intended to be the fourth song on Welcome to Reality, but was left off of the EP before its release.

[2][3] The final two tracks on The Complete Demos—"The Liar" and "Peasant Song"—were recorded that month at the Casbah in Fullerton with Chaz Ramirez engineering.

[3] Frank Agnew and Royer both left the band after a few months, and were replaced by the youngest Agnew brother, Alfie, and by former Mechanics drummer Sandy Hanson for the band's second album, Brats in Battalions (1987), which included new recordings of "The Liar" and "Peasant Song" and a new version of "Do the Eddie" retitled "Do the Freddie".

O'Brien digitally repaired the March 1980 demo tape at his recording studio, DOB Sound.

[3] "The source tapes for that were lost but a collector happened to have four of the five songs on a pretty raw cassette", said Brandenburg.

'"[5] Ultimately the recordings of these two songs were mastered from a Chrome Maxell cassette tape found in Brandenburg's garage.

[3] For the liner notes, Brandenburg, Soto, and Frank Agnew each wrote pieces describing their recollections of and reflections on the band's early years.

Richie Unterberger of AllMusic rated the album 3 stars out of 5, saying that "Although the speed and energy jumps off the VU meter, fans can't get too over the moon, as the fidelity is often pretty mediocre.