Jon Caramanica of "The New York Times" labelled the songwriting exceptional, while praising Mars for being "a model of concision who always knows where the trigger is, and always, always pulls it". He went on complimenting the songs on the record, "these are some of the most energy-infused but profoundly cosseted songs you’re likely to hear all year". "Billboard" magazine's Jason Lipshutz described that the record "succeeds in mixing its safer stylistic choices with its relatively bold ideas". BBC Music's Matthew Horton said that the captivating album showcases the singer's knack for songs with chart potential, while noting the incorporation of rock and soul styles. Sarah Rodman from "The Boston Globe" felt Mars "is trying to rough up his image a bit" as it is undeniable in "his strong, if sometimes oddly lyrically aggressive, second album". Ryan Reed, writing in "Paste", gave "Unorthodox Jukebox" a 7/10 rating, confessing that "Mars still plays the sweetheart card well, but he's proven himself way more interesting as a badass". In a mixed review, Caroline Sullivan from "The Guardian", Kitty Empire from "The Observer", and Andrew Chan from "Slant Magazine" all rated "Unorthodox Jukebox" three out of five stars. Sullivan dubbed it "the same conventional mish-mash as his 6m-selling debut". Empire felt that Mars still lacks a characteristic style, observing "a little more hooliganism" than on his first album and feeling that, "despite its title, [it] deserves your grudging respect" while noting the incorporation of reggae on the record. The critic went on arguing that Mars' songwriting values "narrative arc and internal logic". Closing the review, Chan called it "not an unqualified triumph, "Unorthodox Jukebox" is a step forward" and completed his idea saying that the singer "minor limitation" and "the key to his appeal" on an record that is "a reasonably listenable exercise in genre fetishization." Andy Gill of "The Independent" felt that the singer is a "talented chap", but resorts to imitations of past recording artists on the album, "whose title all but gives the game away". Fiona Shepherd of "The Scotsman" wrote that "Unorthodox Jukebox" is "a safe mixtape, especially compared to what Mars can pull off live with his terrific soul revue band".