These are all 264 songs as of Version 3.12.1. Unreleased songs are under the Misc. section.
88 songs in all IAP packs.
48 songs without IAP packs.
23 songs free, 25 premium songs.
114 event songs, 11 Wave Test songs, 3 special songs unlockable with Frags.
Level cap for non-premium users is: 30
The Giga difficulty was announced during the third event of Dynamix. The first appearance of this song is Version 3.2.3 in Event mode, with GOEMON, Cryonix and 紅 featuring this difficulty.
(with one exception, being Stage5 with a difficulty of 4)