Birdy took inspiration from 1980s artists such as Prince, David Bowie, Madonna and Kate Bush and "more Gothic feeling" from the music of PJ Harvey and Portishead.

Writing for Rolling Stone, Tom Skinner described the track as having an "'80s alt-pop sound, complete with thunderous drums and a power vocal delivery".

[15] Éamon Sweeney's review in The Irish Times assessed Portraits to be "an assured album from an artist who is very comfortable in both her sound and her skin" with praise for Birdy's unique pop interpretation and her voice still being upfront.

[18] Rachel Aroesti of The Guardian positively received the album's 1980s pop nostalgia and named "Paradise Calling", "I Wish I Was A Shooting Star" and "Your Arms" as standouts.

[16] Writing for The Line of Best Fit, Lana Williams called the album as Birdy's "most confident and exploratory project to date" and "an exemplary display of [her] prowess as both a musician, and a songwriter".

[19] Additionally, the "delicate piano notes and soothing vocals" on the track "Your Arms" received praise for harkening back to the style of Birdy's second album Fire Within.

[19] Lucy Harbon, writing for the website whynow, considered Portraits to be complete "reintroduction" to Birdy as a musical artist due to its significant change in direction which makes the album "her boldest record yet".

Portraits is a "refreshing, exciting direction" according to Soloman, who highlighted the "operatic quality" of Birdy's voice that makes for an album that is "sweeping and dramatic".