
Knuckles' Chaotix ( 32X) and SegaSonic the Hedgehog (Arcade) were games that were expected to be on the collection based upon the obscurity theme. The compilation is a GameCube-exclusive in North America, but has also been released on the PlayStation 2 in Europe, Japan and Australia. The North American and European releases only include the two Vectorman titles, in order to keep the former version's ESRB Rating as Everyone and Europe's similar rating. The other four unlockable games are only in the Japanese version: The two unlockable games in all 3 regions are: The collection also includes the six Game Gear games that were absent in Sonic Mega Collection Plus:

Sonic R ( Sega Saturn, port of the PC version, ported by Traveller's Tales).

Sonic the Fighters (Arcade, ported by Sega-AM2).

Sonic CD (Sega CD, port of the PC version, ported by Sonic Team).
