Sonic Mega Collection Plus DX

Sonic Anniversary Mega Collection (known as Sonic 20th Anniversary Collection in Japan) is a system game compilation that has different games based on what system version they are. Ex: If the game is the PlayStation 3 version, it will have Sega Genesis, Sega CD, Sega 32X, and other console games.

Sega Genesis
Sega CD
 * Sonic the Hedgehog
 * Sonic Eraser
 * Sonic the Hedgehog 2
 * Sonic Spinball
 * Sonic the Hedgehog 3
 * Sonic & Knuckles
 * Sonic 3 & Knuckles (Sonic 3 Complete Version in Japanese version)
 * Knuckles in Sonic 2
 * Blue Sphere
 * Dr. Robotnik's Mean Bean Machine
 * Sonic Compilation
 * Sonic 3D Blast
 * Sonic the Hedgehog CD

Sega 32X

 * Knuckles' Chaotix

Sega Saturn

 * Sonic R
 * Sonic Jam

Arcade

 * SegaSonic the Hedgehog
 * SegaSonic Cosmo Fighter
 * Waku Waku Sonic Patrol Car
 * Sonic the Fighters

Dreamcast

 * Sonic Adventure
 * Sonic Shuffle
 * Sonic Adventure 2

Nintendo Feel/Stream
This version of the game confronts to the old but modern games.
 * Sonic Adventure DX
 * Sonic Adventure 2 Battle
 * Sonic Heroes
 * Shadow the Hedgehog
 * Sega Superstars

Nintendo 3DS
This version of the game confronts to handheld games.

Game Gear

 * Sonic the Hedgehog
 * Sonic the Hedgehog 2
 * Sonic Spinball
 * Dr. Robotnik Mean Bean Machine
 * Sonic Chaos
 * Sonic Triple Trouble
 * Sonic Drift
 * Sonic Drift 2
 * Tails' Skypatrol
 * Tails Adventure
 * Sonic Labyrinth

Neo Geo Pocket Color

 * Sonic Pocket Adventure

Game Boy Advance

 * Sonic Advance
 * Sonic Advance 2
 * Sonic Pinball Party
 * Sonic Battle
 * Sonic Advance 3

PlayStation Portable

 * Sonic Rivals
 * Sonic Rivals 2