Highlight "Sonic World" at the main menu and hold [Start] + [A]. A new challenge will begin that requires all 100 rings to be collected within one minute.
Select the original Sonic game. Quickly press Up, Down, Left, Right during the opening sequence. A sound will confirm correct code entry. The, hold [A] and press [Start].
For Sonic 2, enter the options screen, and play sounds "19", "65", "09" and "17".
For Sonic 3, play the previously described sounds, then hold [A] and press and release [Reset]. Select Sonic 3 when the game restarts, then release [A] and press [Up] at the title screen. A sound test option will appear. Use this option to enable level selection.
Play Sonic 3 plus Sonic and Knuckles or Sonic 3 alone. Play as any character and go to "Angel Island". Go to where the swinging vines are and grab one. Then, press [Left]x3, [Right]x3, [Up]x3. A sound will confirm correct code entry. Press [Start] + [Select] to restart the game. Choose the "Sound test" option at the title screen to select all of the Sonic 3 levels and all the Sonic and Knuckles levels.
Change Tails to Miles (Sonic 2)
Press [Up], [Down]x3, [Up] at the title screen. A sound will confirm correct code entry.
Hold [Z] when selecting a movie in the theater. Release the button after the movie starts.
Locate the 3D versions of the classic Sonic power-up boxes in the Sonic World level. Approach the boxes and press [A], [B], or [C] to view codes from other games in the Sonic series.
Insert the game disc into a PC compatible CD-ROM drive to access the following directories and files:
The root directory contains AVI animation files.
The "extras" directory contains screen shots from the game in .BMP format.
The "man_eng1" and "man_jpn4" contains images of the in-game manual in .TIF format.
The "sonic12" directory contains sound files in .AIF format.
Complete all of the world missions in "Sonic World". Go the waterfall and jump on the rising platform. Jump into the large gold ring when the platform is at its highest point.