(This page includes codes and so fourth for the following Sonic games: Sonic, Sonic 2, Sonic Spinball, Sonic 3, Sonic 3D Blast, and Sonic and Knuckles [Sonic 1 locked on])

Sonic

Level Select:  At the Sonic logo screen, press up, down, left, right, repeatedly while holding the A button, until you hear a tone.  When you hear it, press start while still holding the A button.

Debug Mode:  First, apply the level select code, without letting go of the A button select a level.   While in debug mode, the B button enters and exits the mode, the A button selects a different object, and the C button applies the object.

Sonic 2

Level Select:  Select options before starting a game.  Press down, down.  Then, press right 25 times, B, left 4 times, A 5 times, B, A 2 times, right 9 times, B, left 2 times, A, B.   Press Start.  At the Sonic 2 logo screen, while holding in A, press Start 2 times.

Debug Mode:  Apply the level select code.  Highlight Sound Test.  Press B after the following numbers: 1,9,9,2,1,1,2,4.  Hold in A then select a level while still holding it in.

Super Sonic:  First, apply the level select mode, and highlight Sound Test.  Press back 19 times, B, back 3 times, B, forward, B, forward 4 times, B.  Select a level.  Collect 50 rings.   Double jump now.  A double jump is when you press the jump button while still in mid-air.

Sonic 3

Level Select:  When the screen fades black after the SEGA logo, press up, up, down, down, up, up, up, then while holding A select a level.  You must be super super fast to even attempt this code.  It is unbelievably hard to enable.  Only very few people can enable it.

Sonic 3D Blast

Level Select:  At the title screen, select options.  Press B, A, right, A, C, up, down, A.  Then, press Start.

Sonic Cheats:  At the title screen, press up, left, A, and C all at the same time.  Start a new game, pause the game and you may do the following: A= Skips one act.
                                                              B= Skips one level.
                                                              C= Skips to last level.
                                                              X= Adds one life.
                                                              Y= Adds one medal.
                                                              Z= Adds all Chaos Emeralds.

Sonic Spinball

Level Select:  Select options.  Press, A, down, B, down, C, down, A, B, up, A, C, up, B, C, up.  Then, while holding in A, B, or C, exit options and press Start while still holding it A, B, or C in.  If you chose A, you picked the 2nd level; B is the 3rd level and C is the 4th level.

Sonic and Knuckles [Sonic 1 locked on]

Unlocking the game:  At the begining, press A, B, and C all at the same time.

Entering a level code:  Select the code option and you may enter a code for different levels.   Here are some of the level's codes: