Castle Walls

Originally, "Castle Walls" belonged to Diddy, who had commissioned the song for his fifth album Last Train to Paris with his group Dirty Money.

Club wrote that the lyrics of "Castle Walls" "offer similarly incisive and only occasionally self-pitying commentary on the tragedy and triumph of being young, black, rich, famous, and a repeat felon.

raps the verse "See with the Phantoms and Ferraris in the driveway / But you see it came in exchange of a sane man's sanity / Your vision jaded by the Grammys on the mantlepiece / Just switch your camera lenses, you will see the agony" over a "warbling" electronic background and hip hop beats.

"[8] An editor from HipHopDX compared "Castle Walls" to "Love the Way You Lie" by Eminem featuring Rihanna, which was also produced by da Kid.

"[11] Steve Jones, an editor from USA Today, praised Aguilera's appearance on the track and picked it as one of the highlights on No Mercy.

[12] Likewise, Slava Kupersein of HipHopDX and The Boston Globe's Ken Capobianco labelled "Castle Walls" a standout from No Mercy and applauded Aguilera's vocals.

[13][14] Chase McMullen from One Thirty BPM thought that the song "epitomizes the album nearly perfectly", but opined that Justin Timberlake should be the guest vocalist rather than Aguilera.

"[17] Critic Jody Rosen from Rolling Stone was displeased with the lyrics of the song, deeming it "an icky bit of self-pity from a rich and famous man.

"[18] Sean Fennessey of The Washington Post named it an "unfortunately regal perspective",[19] while Pitchfork Media's Tom Breihan called it "downright insulting.

"[6] Prefix Magazine's Dave Park described "Castle Walls" as "cloying" and opined that the track bore an "embarrassing resemblance" to Britney Spears' song "Lucky" (2001).

The track was a success in South Korea, where it debuted at number six on the Gaon International Singles Chart during the week of 5 December 2010.