Kuoko discusses the song Firework stating that it reflects the recent years that have been characterised by uncertainty and the emergence of societal problems. The song is inspired by the feeling of being trapped either at home or within oneself and explores the challenge of seeking growth and happiness in such circumstances. Her authentic and candid song lyrics portray a fictional yet relatable conversation between two individuals. The visualiser accompanying the music video symbolises the empowering feeling of being able to answer a question truthfully, which determines the flower motive. Kuoko frequently incorporates floral imagery in her work, and in this instance, the delicate flowers that appear almost translucent are emerging from a dark place and overcoming obstacles to reach the light.

She has demonstrated her proficiency as a talented composer, songwriter, and producer for several years now. She excels in creating synth-pop music and possesses a pristine singing voice that evokes a sense of melancholy and dreaminess, as evident in her tracks like Floating. Kuoko's music can vary from indie-pop style, such as Hiding in the Dark, to upbeat electronic tracks like Perfect Girl, which are perfect for dancing.