A couple cheats for the classic "Sonic The Hedgehog 1".
Level select:
Press Up, Down, Left, Right at the title screen. A chime will confirm correct code entry. Hold A + Start to begin game play.
All Chaos Emeralds:
Enable the "Level select" code. Select the "Bonus level" option on the level selection screen. Obtain the Chaos Emerald, reset the game, and repeat the process until all of them are in your possession. Allow the game to continue after obtaining the last Chaos Emerald to start in the Green Hill Zone.
Debug mode:
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.
Crazy Sonic:
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.
Bonus points:
Complete Green Hill Zone 1-1 or 1-2 in 29 seconds or less to receive 50,000 bonus points.
Unlimited lives:
Collect the extra life at the very bottom of Green Hill Zone - Act 3. Accumulate 100 rings to obtain another extra life. Collect a third extra life located at the top of the loop-the-loop. Intentionally lose a life and repeat the process.
Control ending sequence:
Enable the "Debug mode" code. Press B when Sonic is running with the animals at the end, then turn back into Sonic. You can nowcontrol yourself.
Hint: Special Zone entrance:
You can almost always have the Special Zone entrance open (the giant ring next to the sign at the end of level Acts 1 and 2) by not losing your rings. If you do lose your rings, when you pass a checkpoint, intentionally die, then continue through the level without losing any rings. This works about 80% of the time.
Hint: Easy Emeralds:
Enable the "Debug mode" code. At the beginning of the level, create 50 rings and have Sonic collect them. Then, take Sonic to the end of the stage where you the giant ring. In the special stage, turn Sonic into an item and bring him to the end of the stage where the emerald is located. Turn him back and he will immediately get the Emerald. Repeat this until you have all six.
Hint: Get all the same color Emeralds:
Enable the "Debug mode" code. While in Special Zone, transform into something then go as far left and down as possible until Sonic stops shaking. Turn back into Sonic. You will fall to a place which is spinning. Look around to find every different Emerald. Note: If you fall off this place, you will fall back to your original location. To prevent this, transform and repeat the process. This works in every Special Zone.
