Writing and musical style
The album's songs were written by Lee and Moody, with Lee the core writer. The two wrote some of the songs when they were 15 and 16. "Imaginary", "My Immortal", and "Whisper" were originally from the duo's independent recordings in the 1990s. Lee composed some of the songs at her house on her keyboard. She wrote songs alone first on the piano or on acoustic guitar, and for Fallen she would write a song and work with Moody to "take it to the finish line." Lee wrote the album's lyrics except "My Immortal"'s, the melodies, much of the music, pianos, and all the choirs; she is credited with the choral arrangements. Lee also honed in on the string arrangements and electronic elements of the album, some of which are in the background.
Most of Lee's writing on Fallen was driven by her mindset during a relationship she was in with an abusive man. Lee wrote "Going Under" about "coming out of a bad relationship". She described the feeling as, "when you're at the end of your rope, when you're at the point where you realize something has to change, that you can't go on living in the situation that you're in." Lee later said that after completing the songs that came out of an abusive relationship, she was listening to her words on "Going Under" and felt that in the chorus she would have liked to have written instead the notion of "I'm leaving and I'm not going to put up with this anymore", thinking to herself "you know what you need to do and you're not doing it." She considered the song the most honest she'd been lyrically and a statement of standing up for herself, in contrast with "Bring Me to Life", which was more of a "cry for help". Billboard said that the "stop/start cadence" of the guitar, "rippling piano and Lee's defiant wail pack a startling wallop".
Written by Lee when she was 19, "Bring Me to Life" is stylistically a nu metal and rap rock song. The label forced them to add the male rapping vocal, which Lee did not want, after originally demanding they include a rap on eight of the songs on the album. She wrote the song after her then-acquaintance and future husband, Josh Hartzler, asked her if she was happy. Lee was in an abusive relationship at the time, and she lied in response. The acquaintance seeing through her facade, as she felt she "was completely outwardly acting normal", inspired her to write the track. The song is about "open-mindedness" and "waking up to all the things you've been missing for so long", Lee said, realizing that "for months I'd been numb, just going through the motions of life." "From the sparkling piano to the epic choruses, to Lee's siren call", Billboard considered "Bring Me to Life" Fallen's "definitive track."
Lee wrote "Everybody's Fool" in 1999 about the lie of pop stardom life and unrealistic, over-sexualized images that warped the youth's expectations. In a VH1 interview, Lee explained that the song came about when her little sister was being influenced by such images. She said it is not about a specific person, but about a collective of the industry that promotes detrimental images and ideals of perfection while "nobody looks like that. It's all fake and it's really hurting a lot of girls' and women's self images." Songfacts stated that the song's concept "seems like it's always relevant". When asked about it in 2016, Lee said she wrote it as "an angsty teenager" about her "frustration with fakeness" that sprung at the time from all the "bubblegum pop acts" that were "put together like products" influencing young people, including her younger siblings. She said that she also acknowledged that "you never know what's going on inside anybody, no matter what they seem like", and it is a song she has "disconnected" from over the years, adding: "It's interesting to write songs when you're in high school and then have them become your most famous songs, because you're stuck singing the stuff you were hung up on when you were in high school when you're 34. And I'm not really hung up about that so much anymore."
"My Immortal" is a piano power ballad, with fictional words written by Moody and the music written by Lee on piano when they were 15, after which Lee added the bridge. The version on the album was a demo from 2000 using a MIDI keyboard and Lee's vocals as a teen, which the label chose over Lee and Moody's re-recording for Fallen. During the production of Fallen, strings by Daredevil composer Graeme Revell were added to the demo recording. The re-recording Lee and Moody made for Fallen was used for the single, dubbed "band" version, featuring guitar, drums and bass after the bridge and a new string arrangement by David Campbell.
"Haunted"'s production emphasizes "feeling overwhelmed by someone’s obsession with you", according to Billboard, with Lee "fighting both being possessed and her desire to give in to it." Lee wrote the song about fiction, thematically "from the eyes of a killer". "Tourniquet" is a reworked cover of Soul Embraced's "My Tourniquet", co-written by Soul Embraced guitarist and Evanescence tour drummer Rocky Gray. Gray told Lee the song was "coming from a Christian standpoint, but it's about suicide. It's from the perspective of someone who has just committed suicide and it's about the controversy in Christianity that if you commit suicide, will you go to heaven or hell?" Lee wrote the cover's melody and added the second verse. The line "I long to die" is from Baz Luhrmann's Romeo + Juliet, a film Lee was "obsessed" with.
"Imaginary" is a song from Lee and Moody's 1998 EP Evanescence. Lee wrote it about feeling the need to retreat to her safe haven as a young teen. Some of her lyrics were from poems she wrote as a seventh or eighth grader. Lee thought it reflected the core sound of Evanescence at the time, and wanted it to be Fallen's fourth single. Billboard described the combination of Lee's lyrics, the piano, "crashing drums" and the Millennial Choir as painting "a picture of the heavens shooting overhead". The midtempo "Taking Over Me"'s lyrics are about Lee being consumed by another person's obsession with her. Partly inspired by her then-acquaintance and future husband, Lee wrote the song as storytelling from the eyes of a stalker.
Lee wrote "Hello" about her little sister who died of an illness when Lee was six years old. The song is about "a day from that time". Lee relived those feelings as a teenager and found it "healing" to write about her experience. The song has a "chilled atmosphere", Billboard stated, and "relates, from a child’s perspective, the dawning agony of realizing someone is gone forever." The lyrics of "My Last Breath" imply a struggle for emotional and physical survival. The song was inspired by the loss from 9/11. "Whisper" is originally from Lee and Moody's 1999 EP Sound Asleep. Driven by guitar and Lee's "commanding voice", it features the "booming" Millennium Choir singing in Latin, ending the album "on a foreboding note", Billboard wrote.
Fallen was regarded as nu metal, alternative metal, alternative rock, gothic rock, and gothic metal. Loudersound described it as a bridge between "nu metal and both the rising symphonic metal and emo scenes". Lee and Moody said they did not consider their music to be "goth", with Moody adding that he thinks the "goth" label came because the songs sound sad and people think that "sad equals dark equals Goth. It's real easy for them to throw us in that box". Moody also disliked the nu metal label, stating: "I think the only nu-metal thing about us is the fact that on one song we have rap and singing". Lee also disagreed with the nu metal tag, attributing it to the rap rock of "Bring Me to Life".
