Project Cross Time Remix

Project Cross Time Remix (or HATRED: The Dark Side for December 2, 2020~February 21, 2021 or The Dark Side) is a remix and actual song that was originally released on September 14, 2020. The song can be heard during Chapter 17 of Story Mode and is pre-loaded before its official release. It's a prequel to Hatred 2: Battle Mode. Beta testing started at October 3, 2020 until December 31, 2020. It was released on January 1, 2021 to mark the beginning of 2021.

Song
The song starts at the beginning of Leakage Voltage, albeit in F sharp minor instead of E. Sixteen beats later, the song transitions to the 7th stage of The One Billion Survivor accompanied with the first scene of Leather composed and remixed by Doin.

Link
https://youtu.be/IAENzq8ATSw - Beta Testing on October 3, 2020

https://youtu.be/nWOQT9W8GaY - Beta Testing on November 12, 2020

https://youtu.be/9x56XZic_sw - Beta Testing on November 22, 2020

https://youtu.be/Mt-Nzy-Ie0U - Full Release on January 1, 2021

Trivia

 * The song was re-adapted in Stepmania instead of Dance Factory.
 * The song was released on January 1, 2021 after Flash ended.
 * Trying to start this level when Chapter 16 in the main story mode hasn't been completed, the specific pop-up message, "This stage ain't powered yet, use Akuma's skills to finish the voltage!" will appear.
 * February 21, 2021 is the date where the song name was renamed from Hatred: The Dark Side to The Dark Side.
 * Unlike any other Splatoon song, this song is powered up via GOUKI-8383H. The boss' weakness is when the Squid Sisters are dancing/singing to this song, and when the dances happen, GOUKI-8383H is simply weakened, allowing for more opportunites to attack the boss level.
 * To avoid copyright infringement, RaidKiller24 added a reverb effect to Leakage Voltage, just like JonathanGD adding reverb to Ouais Ouais in Future Funk II.
 * The music video was unlisted on September 6. It will eventually become public again on mid-to-late September or early October.