Sonic the Hedgehog (Genesis)
Confuse the Demo
While the demo is playing, hold A + B + C. Sonic will get confused, lose his place, and possibly die.
Control Mode
At the title screen, press Up, C, Down, C, Left, C, Right. While playing, you can pause the game and press A to restart, hold B for slow motion, and press C for single frame advance.
Debug Mode
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.

Get all the Emeralds
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 below) 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.

Level Select
At the title screen, hold A then press Up, Down, Left, Right. When you hear the chime, press Start. 

If that doesn't work, try this: at the title screen, press Up, Down, Left, Right, hold A, and press Start. After doing this once, you only need to hold Start + A to enter the level select.


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