The album is primarily an electropop record, also incorporating of other genres such as dance-pop, ambient, bhangra, a cappella, Bhutanese folk, and spoken word.

On 28 March, the track was premiered worldwide through her website via Ustream alongside a remix by British record producer Tim Exile.

[10] During a six-week stay in Hangzhou, Zhejiang, China in the fall of 2011 funded by the British Council and PRS for Music, Heap wrote and recorded the fifth single from the album, "Xizi She Knows", in one day.

[12] On 22 April 2012, "Me the Machine" was premiered during a live performance alongside the release of the crowdsourced nature film Love the Earth, which was co-produced by Heap with her then-partner, Thomas Ermacora.

[26] "Entanglement" is a "sublimely soft ode" to sex sung over an "atmospheric" synth melody,[27] inspired by Heap's "dream scenario" in which she meets the "perfect man" and has "love for life" with him.

[12] The "lush", "energetic" instrumental track "Cycle Song" takes inspiration from Bhutanese folk music and uses samples of sounds recorded during Heap's trip to Bhutan, including temple bells, donkeys, nuns chanting, and traditional drums.

[33] The song's lyrics are written partially as a phone conversation, with Heap singing about yearning for the touch of the person on the other end, and are a social commentary on the effect of technology on relationships.

[35] The "haunting"[25] spoken word piece "Neglected Space" is written from the perspective of an abandoned Georgian walled garden in Bedfords Park.

[12][28] "Run-Time" is a "propulsive"[37] dance-pop[38] track created using a generative or "reactive" music-making fitness app developed by Heap with Intel and RjDj.

[citation needed] The video for "Run-Time" was filmed by Ben Henretig in New York City and shows Heap running and dancing throughout Manhattan, eventually jogging over the Brooklyn Bridge.

[14] Over 300 people volunteered to appear in the "Xizi She Knows" video, which compiles clips from Heap's trip to Hangzhou, including skateboarders surrounded by a circle of taxis, primary school children doing eye exercises, and a 60-year-old man doing a flag dance.

[45] AllMusic's Stephen Thomas Erlewine called the album "cerebral", "worldly", and "ambitious", remarking that it "refus[es] to take a direct route when a detour will do.

Haydon Spenceley wrote for Drowned in Sound that Sparks was "ambitious and well-realised", stating that, although it tried to be "quirky and difficult" and felt "at times over-long and a little self-indulgent", the album was "a wonderfully satisfying listen" and "a pop tour de force of the best kind" made up of "remarkably consistent" songs.

[24] In The Observer, Ally Carnwarth said, "it's hard not to admire the elaborate genesis of Imogen Heap's fourth solo record...persevere and you'll be well rewarded; its feverish, idea-glutted electropop frequently resolves into something thrilling."

[51] Awards and nominations In the United States, Sparks debuted and peaked at number 21 on the Billboard 200 chart, having sold ten thousand copies in its first week.