Sonic Gems Collection for the GameCube is a compilation of many different and classic Sonic video games. It has Sonic CD for the Sega CD, Sonic the Fighters which was originally in the arcade, and Sonic R for the Sega Saturn. It also has bonus Game Gear games like Tails' Adventures, Tails' Sky Patrol, Sonic the Hedgehog 2, Sonic the Hedgehog Triple Trouble, Sonic Drift 2, and Sonic Spinball. This even has loads of unlockable content including two games (Vectorman and Vectorman 2) and a museum mode in which you can unlock artwork and songs from the games.
Sonic CD for the Sega CD (port of the PC version)
Sonic the Fighters for (Arcade)
Sonic R for the Saturn (PC version used)
Game Gear games
Tails' Sky Patrol
Sonic the Hedgehog 2
Sonic the Hedgehog Triple Trouble
Sonic Drift 2
Bonanza Bros. (JP only)
Streets of Rage (JP only)
Streets of Rage 2 (JP only)
Streets of Rage 3 (JP only)
IGN's Juan Castro gave it an overall score of 7.5 (Good) stating that "In the end, Sonic Gems Collection is a decent compilation, even though it’s not as solid as Sonic Mega Collection." while GameSpot's Ryan Davis gave it a 6.3 (Fair) rating.
While it says on the cover of the Sonic Gems Collection case "Only for GameCube", a PlayStation 2 version of the game was released but not outside Japan. An Xbox version was planned but cancelled.
The Bonanza Brothers, Streets of Rage, Streets of Rage 2, and Streets of Rage 3 are not available on Sonic Gems Collection outside Japan in order to keep ESRB's everyone rating.
Games from Sonic Mega Collection Plus can be unlocked in a "demo" form. These are actually the full games, but play automatically begins at the last level or final boss with a time limit imposed on play time. There are cheat device codes available which will freeze the time limit, allowing the game to played through fully.
Wonderboy III: Monster Lair, Wonderboy in Monster World, WonderBoy IV, and Sonic Eraser were all games going to be incuded in the game but were left out instead. SegaSonic the Hedgehog was also planned to be in the game but due to emulation issues was left out. There is also an entire art section of the museum dedicated to Knuckles Chaotix, which may indicate that Chaotix may have been planned for inclusion, but was left out instead.
Until Sonic Gems Collection's release, Sonic The Fighters had never been released outside the arcades.