This is addtional content that enables the following songs:

POKER FACE
Paranoia
Trance Dance Anarcky
The Karasu Wind
SACRIFICE
Museimei Saafesu
PanneDemonology
Christmas Bomb!!
Uki Yomichi (feat. Ranko, Utenkekkou)
Hell's Sun
Gensou Syndrome
Entrusting this World to Idols(marasy piano ver.)
Hitorisizuka（Marcia Cover Version）
Saigetsu
Dial Connected
Bad Apple!! feat.nomico (Tetsuya Komuro Remix)
Hanamaru! Saikyo Hyper Cirno
Tenkyuu Tenge Otohanabi
Howling
Onerule・Gamechanger
Genmu
Gensou no Satellite
INTERNET SURVIVOR
M. O. N. E. Y. (Dankagu Special REMIX Ver.)
Love-colored Master Spark

More details on the official game page of Extra Song Pack 1 ...