He also collaborated with other songwriters and producers, including Lindsay Rimes, Khalil Walton, Michael Gerrard, and Jenna & Wac of Tonight Alive. In an interview with "The Sydney Morning Herald", Mastin described the album's sound, saying "[It's] a lot of fun. It's rock blended with everything. If you think of your favourite rock song, it's that combined with pop stuff and club stuff [...] to make it awesome. It's Reece from all angles, really – it's everything I could think of." Musically, "Beautiful Nightmare" is of the pop and rock genres. Its first song "Addictive" is a synth-driven rock song, which features "light reggae segments". The second song "Rock Star" is a pop rock song, which features "American sounding guitar riffs". A writer for Take 40 Australia likened the song's sound to Wheatus and Jimmy Eat World. Cameron Adams of the "Herald Sun" noted that the song "channels" Wheatus' "Teenage Dirtbag" (2000) Avril Lavigne's "Sk8er Boi" (2002). The album's title track "Beautiful Nightmare" is a dubstep and horror rock song "slightly reminiscent of Muse". "Stars" has been described as a "romantic song", which sees Mastin "heading back to more traditional pop". In an interview with the "Herald Sun", Mastin revealed that the song is about his girlfriend Rhiannon Fish. The album's fifth song "Dirty Paradise" is a pop punk song, which "features fast lyrics such as 'You gave it up last week / now I've been losing sleep / thinking about what we used to do'". "Alive" is an "uplifting" rock song, which uses the tom-tom drum. Its lyrics depict the tale of Mastin "learning to believe in himself again". He stated that the song is about his "X Factor" mentor Guy Sebastian, saying "It's an important thing for me; that's where it all started for me. I changed so much over the show and Guy definitely helped with that." "She's a Killer" features a "funky Panic! at the Disco-esque" introduction and contains lyrics about "a super-hot girl". "Freakshow", the ninth song from "Beautiful Nightmare", is a contemporary rock song with influences by Muse. "Shut Up & Kiss Me" is an upbeat pop punk song, which contains lyrics about "making out with a girl".