Sonic The Hedgehog

Hold A + B + C during demonstration mode for force Sonic to run into objects and act strangely. Note: This may also be done during the ending sequence after completing the Final Zone.

Press Up, C, Down, C, Left, C, Right, C, Start, then hold A at the title screen. Continue to hold A until game play begins. Screen coordinates will appear instead of a score and the number of objects displayed will appear instead of the time remaining. Use one of the following controller actions to enable the corresponding debug code. Note: This code may only be enabled on the first version of the game.

Object transformation
Press B during game play to change Sonic into a game object. Press A to change into a new object. Press C to place an object on the screen. Press B again to revert back to Sonic. Note: The type of object that may be selectable will vary from level to level.

Invincibility
Sonic is, by default, invincible in debug mode. Note: Sonic can still drown, be crushed, fall and die, etc. He is only invincible to enemy attacks.

Slow motion
Pause game play and hold B.

Restart
Pause game play and press A.

Frame advance
Pause game play and press C.

In the Japanese version, press press Up, C, Down, C, Down, C, Down, C, Left, C, Right at the title screen. A sound will confirm correct code entry. Pause game play, then press the buttons described above to activate slow motion, restart, and frame advance.

Enable Control Mode. After pressing Start to begin a game, hold A until you see Sonic. If you
see a bunch of hex numbers on the top of the screen, you're in Debug Mode.

To start debugging, press B, then you can select any sprite in that level and put it on the screen.
To select a different sprite, press A, and to place it on the screen, press C. Note that sprite
selection is different from Zone to Zone. Also, instead of displaying the time elapsed, it displays
the number of sprites currently on the screen. Control Mode functions work as well.

Note: This only works on the first production releases of Sonic.

During the demo, hold C. Sonic will crash into walls and get hit by enemies.

In Green Hill Zone - Act 3, there is a 1-Up at the very bottom of the level. Collect it along with
enough rings to make 100 for a second life. Next, grab the 1-Up at the top of the loop-de-loop
and die. Repeat until you have enough lives.

This cheat allows you to start at the First Level with all the Emeralds, and with lots of Continues.
Use the Level Select cheat (see above) to get to the Special Zone. When you get the Emerald,
and have entered into the First Zone, press Reset.

Use the Level Select cheat to get to the Special Zone again. When you get the next Emerald, and
have entered the First Zone, press Reset again.

When you have all the Emeralds, continue on with the first level. You get to keep the Emeralds
and the Continues accumulated so far.

Enable the "Debug mode" option. Collect fifty or more rings (or just transform in a ring and get fifty or more). Go to the end of the level and do not pass the ending sign. Press B button and look through your transformations. You should find the Big Ring (at the end with fifty or more rings) in your options for transformations. You can now place another Big Ring. If you place a Big Ring before you pass the sign and behind the sign then go inside the ring the game will glitch. You cannot move (including using Debug mode), see yourself, or hear yourself. Note: This was done in Green Hill Act 1;

Enable "Level select" and "Debug mode" codes. Put a lamppost just before the sign at the end of the level. Press B to transform back into Sonic and hit the lamppost. Get out until the lives read "1" at the bottom of the screen. Spin the sign to end the level. Wait until Sonic walks out of the screen. Enter debug mode and go under the sign to get out again. The "Game Over" message will appear while the credits are being shown. You now have unlimited lives.

Enable the "Debug mode" code. Go to Green Hill Act 2 and find the location with a spinning wheel, two or three falling blocks, and a floor of spikes. If needed, use "Debug mode" to find this area. Make all the blocks fall and land on the spikes, but away from the land at the end of the blocks. You should lose all of your coins and bounce forever until you reset. Debug mode is needed for default invincibility. For an alternate method, get all the Chaos Emeralds for invincibility for spikes enemies, etc.

Enable the "Debug mode" and "Level select" codes. Select Special Stage at the level selection screen in Debug mode. Turn into an object and exit the compressed area (The place that Sonic is always in without Debug mode). When you think it is far enough, turn back into Sonic. You may seem to fall for awhile, but if you wait long enough you will find a "W" (possibly for the renamed Clock Work Zone, that was later renamed Scrap Brain Zone. They renamed the zone because they forgot the "W" in the games coding) labels that say 1 Zone; 2 Zone; and 3 Zone. There is also the Sonic !-Up as seen in the manual, but never seen in the Special Stage.