Yes, the music is Let It Go by Idina Menzel. It is sorta unfitting for this, but, the song is nice. (The piano fits, right?) Credit to @tygreenie and @phineasandferbfan9
On May 20th 2014, Nintendo Wifi connection is shutting down for the original Nintendo DS, DSi and the Wii. This is due to financial problems with Nintendo lately... R.I.P Nintendo Wifi 2004-2014
