It is a compilation that contains both Psyvariar -Medium Unit- and -Psyvariar Revision-.
New features include:
Option to use a separate button to roll
SECRET LAB jukebox
Ability to display hit boxes[1]
Two special editions were also available in Japan. The Special Sound Box included an audio CD of the game's soundtrack, and the Special Capture Box included a gameplay DVD of both games being fully completed by expert players. The PlayStation 2 version of the individual games were later released separately as budget range titles.
European version retained all the features of the Japanese release and includes a 60 Hz mode.
Source: Wikipedia, "[en.wikipedia.org/wiki/Psyvariar%23Psyvariar_-Complete_Edition- Psyvariar]", available under the CC-BY-SA License.