Stephanie Choi of Hello Asia and Gina Mei of Cosmopolitan praised the nostalgic feel of the video, as several aspects — the costumes, the simple, white backdrop, and old film transition techniques — reflect the retro style of the late 1980s and 1990s.

[13][14] On October 4, Shinee performed the title track "1 of 1" publicly on stage during their showcase for the album at the SM Town Coex Artium.

Onew was unable to participate in the dance sequences due to his injury, but confirmed he was receiving treatment and was almost completely recovered.

[20][21] As part of the promotion, the group members also guested on several variety shows including Happy Together 3,[22] Weekly Idol,[23] Knowing Bros[24] and KBS World's Guerilla Date.

[17] Jonghyun took part in composing the song "Prism", a two-step pop number featuring piano and synthesizer chords.

[5][30] British duo LDN Noise, who wrote Shinee's previous songs "View" and "Married to the Music", participated in producing the seventh track "Shift".

[34] The music video for 1 of 1 was released on October 5, 2016, through SM Entertainment's official YouTube channel, and takes inspiration from the 1990s—from the group's wardrobe to their dance moves.

[37] Jeff Benjamin of Fuse praised the atypical portrayals of beauty, stating: "from the female co-stars' rock messy hairstyles, dark lipsticks and eyeliners, and super-casual clothes, to the guys' offbeat hair colors (shoutout to Minho's turquoise-gray dye) and outfits, nothing is standard "K-pop" here".

Both Tamar Herman of Billboard[38] and Benjamin compared the title song to the music of groups like New Kids on the Block, New Edition and H.O.T.

He also compared the focus on singing directly to the listener and using the "you" pronoun to The Beatles' early material like "From Me to You" or "I Wanna Hold Your Hand".

[36] Stephanie Choi of Hello Asia and Gina Mei of Cosmopolitan compared the fashion style, filming techniques and overall aesthetic to the late 1980s and 90s, giving the music video a feeling of nostalgia.

[44] According to Lee Mi-hyun of JoongAng Daily, the most noteworthy feature of the repackage album was to pick "Tell Me What to Do" as the title song.

He stated that it is an unfamiliar sound for a ballad, but is an interesting song choice because it shows the growth of Shinee's musicality, emphasizing that the group's "singing power is something, which needs to be carefully talked about".

[45] Sung Mi-kyung of OSEN likewise stated that Shinee have proved a broader musical spectrum through ballads with "outstanding sensitivity".

He added it's done in a way that one can easily sing along with and stated that despite being released late into the year, the blend of melancholy and hope is helping the song to make a "last-minute run to be named one of the best K-pop singles of 2016".

[47] Tamar Herman of Billboard also praised the strong vocal performances from the members, particularly Onew and Taemin's sonorous belts, that made "Tell Me What to Do" the group's "most emotive single of the past few years".