[11][12][13][14] Heartbreaker was created during a three-week period in November 2020 at a rented Bucharest mansion with two recording studios, in which Inna resided with Romanian songwriters and producers Sebastian Barac, Marcel Botezan, Ciente, Alexandru Cotoi and Minelli.

[29] Bradley Stern of MuuMuse called Inna a "solid supplier" and "damn prolific", praising her decision to issue a completely new body of work with Heartbreaker and not stretch it out by not adding the previously released non-album singles to its tracklist.

The album opens with the Arabic music and reggaeton-inspired "Maza Jaja"[30] and "One Reason", with Stern commenting that the latter is "bound to be on heavy rotation at my Russian barbershop in Midtown that solely blasts deep house dance hits".

[26][31] Dance-Charts' Manuel Probst commended Heartbreaker as "top notch" and singled out "Flashbacks" as his favorite track, noticing "atmospheric" sounds, a piano loop and slap bass in its composition.

The Spanish-language "label brag" "Gucci Balenciaga" includes the explicit lyrics "me importa una mierda" (Spanish: "I don't give a shit"),[31] and is followed by the title "Heartbreaker", which InfoMusic's Alex Stănescu picked as the album's highlight, noticing its oriental influences as well as the use of a synthesizer and vocal chopping.

[26] While Stern likened "Sunset Dinner" to American recording artist Britney Spears' "Change Your Mind (No Seas Cortes)" off her 2016 studio album Glory, he praised "Thicky" as "stand[ing] out above the rest".

[44][45] All tracks lyrics written by Elena Alexandra Apostoleanu (Inna) and Luisa Luca whereas musical composition was done by producers Alexandru Cotoi, Sebastian Barac, Marcel Botezan and David Ciente.