This hack back-ports scoring modes and game systems from modern versions of Radiant Silvergun into the Saturn and ST-V versions of the game. Namely, this adds “Ikaruga Mode” from the Xbox 360 version, as well as the 2-button “overseas” mode exclusive to the ST-V version. In addition to these ported modes, there’s a new Special scoring mode which combines the original scoring system and the Ikaruga scoring systems in a different manner.
The Saturn version always has Option+ (mostly filled with assistance options) unlocked, and adds two new options to control the new features. The settings are saved along with the other settings, so you can set and forget.