- Sonic the Hedgehog (JP and US versions)
- Sonic the Hedgehog 2
- Sonic the Hedgehog 3
- Sonic & Knuckles
- Sonic 3D Blast
- Sonic Spinball
- Dr. Robotnik's Mean Bean Machine
Japan-exclusive Unlockable Games (also found in Plus)
- The Ooze
- Comix Zone
How to unlock
- Sonic 3 & Knuckles: Play Sonic 3 and Sonic & Knuckles 20 times each.
- Knuckles in Sonic 2: Play Sonic 2 and Sonic Spinball 20 times each
- Blue Sphere: Play Sonic the Hedgehog and Sonic 3D 20 times each.
- Flicky: Play Dr. Robotnik's Mean Bean Machine 30 times. Alternatively, have a Sonic Adventure 2: Battle save file on your memory card. (This is only for the Gamecube version of Sonic Mega Collection. This can't happen in any copy of Sonic Mega Collection Plus)
- Ristar: Play Knuckles in Sonic 2, Sonic 3 & Knuckles, Blue Sphere and Flicky 30 times each.
- Comix Zone: Have 40 hrs of game time on Sonic Heroes.
- The Ooze: Have 40 hrs of game time on Sonic Heroes.
- For Sonic Mega Collection Plus, you can unlock The Ooze and Comix Zone by saving Sonic Heroes game data on Xbox, Xbox 360, PlayStation 2, or PlayStation 3 consoles.
- History of Sonic comics (readable)
- Sonic's Firsts (readable)
- Sonic the Hedgehog Covers 1-110
- Knuckles the Echidna Covers 1-32
- Sonic Super Special Covers 1-15
- Misc. Covers
- 6 Sonic pictures
- 6 Tails pictures
- 5 Knuckles pictures
- 6 Doctor Eggman pictures
- 9 Other pictures (Amy Rose, Shadow, Rouge, Big the Cat, E-102, Chao, Hero Chao, Dark Chao, Cream and Cheese)
- 15 Misc. pictures (4 package designs (Sonic Adventure, Sonic Adventure 2, Sonic Adventure 2 Battle, Sonic Advance), 6 Sonic Adventure CG designs, 5 pictures of a calendar, calling and Christmas cards, magazine illustrations)
- Sonic CD Intro
- Sonic CD Ending (the good and bad endings included together)
- Sonic Adventure 2 Battle
- Sonic Advance 2 Preview
- History of Sonic
- This was the first Sega game to reunite the classic "SE-GA" chant since the early-late 90s' (Sonic 3D Blast has the "SEGA!!" scream), likely included due to the retro nature of the compilation.
- Sonic CD was originally going to be on the compilation, but was cut due to emulation problems. This game was later released on Sonic Gems Collection, where the PC version game code was ported (and hi-quality versions of the anime clips replaced the older ones). SEGA gave the excuse that there wasn't enough space for the game.
- Sonic Mega Collection Plus was combined with Super Monkey Ball Deluxe for Xbox in a Platinum Family Hits package.
- In the extras, there is artwork of Cream the Rabbit from the then-upcoming Sonic Advance 2. At the time, she was a new character to the series. There is also a trailer for the game. In Japan, this game was released at the same time as Sonic Advance 2.
- The GameCube version has the US and Japanese version of the original Sonic game, but if you set the framerate to 50fps, this will unlock the European version with slower music.
- The US PS2 version of Sonic Mega Collection Plus (in Sonic and Knuckles) has a glitch where you can play as Knuckles in the Death Egg Zone and in the second-to-last boss against Dr. Robotnik (before the Doomsday Zone). This is because, if you enter the Level Select screen through the in-game cheat code, Knuckles can enter the Death Egg Zone due to a mistake from a computer programmer forgetting to block off Knuckles's data from that particular level.
- It should also be noted that Knuckles is unable to beat the first boss of Death Egg Zone, as he cannot jump high enough to deal damage. However, he can beat the second level and second boss if the player is quick enough. The boss can also be beaten through debug mode if one places springs so Knuckles can jump high enough to attack.
- Sonic Mega Collection was the first ever Sonic game with a PEGI 12+ rating and the PEGI 12+ rating was followed by Shadow the Hedgehog (2005 Game).
- A Remix of the Title Screen music can be heard, during the Network Mode in Sonic Generations.
Sonic Mega Collection Plus
Sonic Mega Collection Plus (ソニック メガコレクション プラス Sonikku Mega Korekushon Purasu?) is a update of Sonic Mega Collection for the PlayStation 2 and Xbox consoles. A PC version was also released in Europe. This edition includes the addition of six Game Gear games, the two games that were included in the PC version (The Ooze and Comix Zone), new artwork and movies, a new in-game menu, and a mid-game saving feature. It is, however, missing six Sonic Game Gear games that were included (along with the six included in this collection) in Sonic Adventure DX: Director's Cut, but they would later appear in Sonic Gems Collection. In addition, only the Japanese version of the original Sonic the Hedgehog is available. It is the first Sonic game with a 12+ PEGI rating. The PC version was released on March 6, 2007 in North America. The original packaging says it's a CD-ROM, but it is instead a DVD-ROM; it will not play in a CD-ROM-only drive.
The following Game Gear games were added:
- Sonic the Hedgehog
- Sonic Chaos
- Sonic Drift (the second time it was released in Europe and North America)
- Sonic Labyrinth
- Dr. Robotnik's Mean Bean Machine
- Sonic Blast
The PlayStation 2 version, however, suffered from a few minor emulation issues. Sound effects in the first Sonic the Hedgehog would sometimes be delayed, the music volume was incorrect in some games, and the screen resolution in both the PlayStation 2 and Xbox versions differed from the Mega Drive originals (this was a normal feature, however). These emulation issues were caused by Sonic Team's somewhat lacking experience developing for the PS2. The Sonic CD introduction and ending, as well as the preview videos for Sonic Adventure 2: Battle and Sonic Advance 2 from the GameCube version, were swapped with Sonic Heroes movies (all of which appear in Sonic Heroes). The Xbox version does not have the Korean Sonic Heroes boxart. The PC also suffered from issues with analog gamepad controllers and players with such controllers have to resort to using third-party applications such as Joy2Key in order to use their preferred control method.
Reaction for Sonic Mega Collection was mostly positive.The game sold very well across all platforms, attaining two Best Seller status: Player's Choice (GameCube), Greatest Hits (PlayStation 2), and Platinum Hits (Xbox). In particular, the PlayStation 2 version and GameCube version both sold over two million copies.