The album has been considered influential on the emo music genre due to its unique style at the time, and it has been certified gold by the British Phonographic Industry.

My Chemical Romance was formed after the band's frontman, Gerard Way, witnessed the collapse of the World Trade Center during the September 11 attacks.

[1] Soon after the band formed, they created three songs–"Skylines and Turnstiles", "Cubicles", and "Bring More Knives"–in a makeshift studio set up in Pelissier's attic.

[8] After the song's final version was complete, Pencey Prep frontman Frank Iero, who had previously already witnessed the band's past recording sessions, joined My Chemical Romance.

[14] Several songs on the album were influenced by comic book themes, implementing ideas such as gothic imagery and zombies.

[12] Due to the differences in sound and lyrics between those bands and My Chemical Romance, the latter frequently rejected the emo label, though they have still been considered figureheads within the genre.

[12] Lyrically, the album covers themes like depression, pessimism, anger, and disillusionment,[22] with the settings of each of the songs varying.

[25] It opens up with an instrumental cover of the "Romance" guitar piece,[26] before directly leading into "Honey, This Mirror Isn't Big Enough For The Two of Us",[25] a metalcore influenced[27] song primarily about consuming antidepressants and alcohol.

[34] "Skylines and Turnstiles" is centered around the September 11 attacks, focusing on the emotions that Gerard felt after witnessing the events.

[35] "Early Sunsets Over Monroeville" was inspired by the 1978 zombie horror film Dawn of the Dead, telling the story of a group of lovers attempting to survive the apocalypse.

[36][32] The song has generally been considered an analogy on Gerard's willingness to die for his loved ones based on the text present in the album's inlay.

Over the course of six months, the band would play a variety of shows at different venues, ranging from garages and basements to dive bars.

Furthermore, Iero also stated that a large amount of the original 100 copies were misprints, consisting entirely of unknown mariachi songs instead of My Chemical Romance tracks.

[38] Following the radio premiere of "Vampires Will Never Hurt You", two singles from the album were released: "Honey, This Mirror Isn't Big Enough For The Two Of Us" on December 13, 2003[42] and "Headfirst for Halos" on April 3, 2004.

[21] Rolling Stone described the album as reading like a list of things that caused Gerard to "grow up too fast", and that it was "designed to make you feel sixteen-years-old again, experiencing every heartache as if it's on scale with the World Trade Center crumbling down".

Rolling Stone praised the music, writing that it combined with the lyrics to help create what he compared to the "frenetic build-up to an over-the-top climax that you find in horror movies".

[16] Drowned in Sound believed that the album had "undeniable fragmentation" as a lack of consistency between its tracks, though felt that this allowed the songs to stand on their own.

[12][26] In a 2022 retrospective article, Chris Payne of Stereogum wrote that while the album wasn't My Chemical Romance's best work, it helped combine several different genres into one, and stated that the album was a good start to "one of the greatest three-album runs in rock history", with the other two being Three Cheers for Sweet Revenge and The Black Parade (2006).