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Sonic News Network
Sonic News Network

Debug Mode activated in the original Sonic the Hedgehog. Notice the debug coordinates on the upper-left corner.

Debug Mode is the general name for a category of video game features designed to assist game developers in testing and debugging their code. For instance, a menu that allows the user to edit level layouts or test character abilities may be described as Debug Mode. Although Debug Mode is commonly seen in video games under development, it tends to be removed or hidden once the game is released, as it grants abilities beyond those intended for the player.

Some Sonic the Hedgehog games, especially those released for the Sega Mega Drive, are notable for allowing players to easily access Debug Mode by inputting a cheat code.


Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic the Hedgehog CD, Sonic the Hedgehog 3 & Knuckles, and Sonic Mania each have a Debug Mode that activates the same basic set of features. Generally, the HUD changes to show the player's coordinates in place of the score counter. In Mega Drive and Sega CD games, the player may press B Button (Sega Genesis).svg to activate and deactivate object placement mode, which replaces the player character with an item that can be freely moved around the stage with Controlpadds.png and placed by pressing C Button (Sega Genesis).svg. Pressing A Button (Sega Genesis).svg will cycle through placeable objects, and while holding A Button (Sega Genesis).svg, pressing the C Button (Sega Genesis).svg button will cycle backwards through the list of objects. These lists usually include the current Zone's Badniks, certain platforms, and other obstacles or scenery. However, some Zones allow the player to place objects that are not found in normal gameplay, such as scrapped enemies. While Debug Mode is active, the player can perform certain actions while the game is paused. Pressing A Button (Sega Genesis).svg will return to the title screen, holding B Button (Sega Genesis).svg will cause the game to run at half speed, and C Button (Sega Genesis).svg will advance the game by one frame. Although each game's Debug Mode shares the same basic controls, there are also slight differences between each.

In Sonic the Hedgehog, Sonic cannot die from spikes while Debug Mode is active, simply bouncing off them in his hurt animation until he is no longer touching them.

In Sonic the Hedgehog 2, Sonic can enter object placement mode but Tails cannot. Additionally, in this game and Sonic the Hedgehog 3 & Knuckles, "Night Mode" may be activated by holding C Button (Sega Genesis).svg while entering a level from level select. This highlights foreground sprites and darkens background sprites.

In Sonic the Hedgehog 3 & Knuckles, the player can press both C Button (Sega Genesis).svg and B Button (Sega Genesis).svg to cause the current character to quickly scroll through all his available sprites. These sprites may be seen more clearly by pausing and pressing C Button (Sega Genesis).svg to advance one frame at a time. Also, pressing A Button (Sega Genesis).svg while not in object placement mode will reverse gravity and cause objects to be placed upside down as well.

Examples of Debug Mode in action


Activating Debug Mode

The earlier installments in the Sonic the Hedgehog series are known to have specific cheat codes to activate debug mode, while games released after Sonic & Knuckles can only access Debug Mode with hacking or cheat cartridges such as GameShark. The following list shows how to activate Debug Mode in certain Sonic games without using cheat cartridges:

Sonic the Hedgehog

  • Original: At the title screen press ↑ C Button (Sega Genesis).svgC Button (Sega Genesis).svgC Button (Sega Genesis).svgC Button (Sega Genesis).svg. If done correctly, a Ring chime will play and holding A Button (Sega Genesis).svg and start will begin the game with Debug Mode. In revisions of the game, the code is changed to C Button (Sega Genesis).svg C Button (Sega Genesis).svg ↑ ↓ ↓ ↓ ← → if played on a Japanese console.
  • 2013 re-release: At the Level Select Sound Test, play the following tunes in order: 01, 09, 09, 01, 00, 06, 02, 03. Then after selecting a Stage to play, the player may tap the HUD on the upper-left corner of the screen to activate Debug Mode. Once there, the player can cycle through the placeable objects by tapping the minus or plus buttons, move around with the directional pad and place them by tapping the jump button. To exit Debug Mode, the player must tap the HUD again.

Sonic the Hedgehog 2

  • Original: The Level Select screen must be activated and then entered. There, play the following music in order: 01, 09, 09, 02, 01, 01, 02, 04 at the Level Select's Sound Test section. Then select a Zone, hold A Button (Sega Genesis).svg down and press start.
  • 2013 re-release: After accessing the Level Select, the player has to play the same music tracks as the original release in the Sound Test. The controls remain the same from the 2013 re-release of the original Sonic the Hedgehog and in addition, the player can return to the Level Select anytime while in Debug Mode by tapping the top right corner of the screen where the pause button would be.

Sonic the Hedgehog CD

  • Original: First, input the Sound Test code at the title screen. Then set the Sound Test to show FM#40, PCM#12, and DA#11, and press the start button. A bonus picture featuring Tails with the words See You Next Game" from the character's designer Yasushi Yamaguchi will show before returning to the title screen.
  • 1996 PC Release: As before, first enter the Sound Test code at the title screen. In the Sound Test, input PCM#12 and DA#11 and then press SPACE in the keyboard.
  • 2011 re-release: First unlock the Sound Test. As in the 1996 PC release, the player needs to input PCM#12 and DA#11, then press start.

Sonic the Hedgehog 3 & Knuckles

  • Sonic the Hedgehog 3: The player has to enter the Level Select code and head to the Level Select screen. Here the player has to hold A Button (Sega Genesis).svg down, select one of Zones/Acts in the game and then press start.
  • Sonic the Hedgehog 3 & Knuckles: The player has to activate Level Select code and then head to the Mushroom Hill Zone (Act 1 is the fastest and recommended choice). Here the player has to jump on one of pump elevators and then press ← ← ← → → → ↑ ↑ ↑. If done correctly, the Ring sound is heard. Following this, pause the game and press A Button (Sega Genesis).svg to go back to the title screen and then head to 1 Player or Level Select. There, select a Zone, hold A Button (Sega Genesis).svg down and then press start.
  • Sonic & Knuckles: Debug Mode is normally inaccessible in Sonic & Knuckles alone, but by activating Debug Mode in Sonic the Hedgehog 3 & Knuckles and then triggering a glitch using S monitors, the game can mistakenly switch to Sonic & Knuckles with Debug Mode still active. This has the interesting side effect of Sonic & Knuckles showing a Marble Garden Zone demo, possibly part of leftover data.
  • Knuckles the Echidna in Sonic the Hedgehog 2: The player has to activate the Level Select code and head to the Level Select screen. Here, play songs 01, 09, 09, 04, 01, 00, 01, 08 in order at Sound Test part and the Ring chime can be then heard. Then press A Button (Sega Genesis).svg down, select one of Zones in the game and press start.

Sonic Spinball (8-bit)

Sonic Spinball (8-bit) has a different version of Debug Mode, consisting of several cheat codes that each activate different secret effects. On the left edge of each stage is a hidden chamber that contains three Item Boxes. Each of them contains a 1-Up, a Continue, and a special variant with 見る on it (Japanese characters for "look"). Breaking this Item Box will give a hint for a secret code. The codes are as follows, to be played in order at the Sound Test of the game in options menu. Inputting the code correctly makes the screen shake slightly. List of codes and their purposes:

  • 0, 8, 3, 1, 7, 1: Gives the player full codes instead of hints when the player hits the Item Box with 見る kanji on it in each stage of the game.
  • 0, 2, 1, 1, 6, 6: Makes Sonic's sprites in general three times larger. This does not affect gameplay.
  • 0, 9, 0, 1, 6, 8: Allows Sonic to move freely in the stage by pausing and pressing 2, then using the D-pad to move around.
  • 0, 2, 1, 5, 6, 6: Gives the option to skip to the next stage by pressing down on the D-pad.
  • 0, 4, 2, 5, 5, 7: Makes the background music in the stage extremely fast.

Sonic Mania/Sonic Mania Plus

In Sonic Mania, and its expansion Sonic Mania Plus, players can unlock Debug Mode by obtaining at least sixteen Medallions from the Bonus Stage. This will unlock Debug Mode as a feature in "Game Options" that can be toggled on or off. Prior to Version 1.04/RC 1.05.0713, the player could only do this in No Save mode.

Originally, there was a cheat code for unlocking Debug Mode. First, the player had to hold PSXButton.png/A button.png/Switch b.png and PSSquareButton.png/X button.png/Switch y.png, then press any other button to access a special Level Select screen in the style of Sonic the Hedgehog 2. After selecting a level, the player then had to press PSTriangleButton.png/Y button.png/Switch x.png to access Debug Mode in-game. However, this cheat code was patched out as of Version 1.03.


  • In the beta version of the original Sonic the Hedgehog, the Debug Mode was activated by default.
  • Some Debug Mode and Level Select codes in the sound test spell out calendar dates.
    • Playing songs to activate the Debug Mode in Sonic the Hedgehog 2 can format date 24 November 1992, the game's worldwide release date.
    • This is similarly repeated in Knuckles the Echidna in Sonic the Hedgehog 2, where the code can format date 18 October 1994, when Sonic & Knuckles was released in the United States and Japan.
    • In the 2013 re-release of Sonic the Hedgehog (1991), playing songs in the Sound Test for activating Debug Mode can format 23 June 1991. This is the release date of the original Sega Genesis version of the game in United States and Europe.

Debug mode in the cancelled Sonic X-treme.

  • The cancelled Sega Saturn game Sonic X-treme also has a Debug Mode in the 714 build. It is activated by pressing Start and then B Button (Sega Genesis).svg. Unlike other games, it Is available from the start and it cannot be exited. The only object the player can place is a Ring, by pressing Start and then B Button (Sega Genesis).svg.
  • The message the player receives for unlocking Debug Mode in Sonic Mania is a reference to "Sonic - You Can Do Anything", the theme song of the PAL and Japanese versions of Sonic the Hedgehog CD.
  • Beta builds from certain games (particularly Sonic the Hedgehog 2), such as the Simon Wai and Nick Arcade prototypes, also feature Debug Mode, albeit in a rather unfinished state, often only allowing the player to place Rings and Super Ring monitors.
Navigation Templates to Debug Mode

Main article | Staff | Manuals | Glitches | Beta elements | Gallery | Pre-releases (Nick Arcade, Simon Wai) | Re-releases (Knuckles in Sonic 2, 2006, 2013, 3D, Sega Ages)

Main article (Sonic 3 & Knuckles) | Credits | Manuals | Glitches | Beta elements | Gallery | Re-releases (Sonic & Knuckles Collection)

Main article (Blue Sphere, Knuckles in Sonic 2, Sonic 3 & Knuckles) | Credits | Manuals | Beta elements | Gallery | Re-releases (Sonic & Knuckles Collection)

Main article | Staff | Glitches | Beta elements | Pre-releases (1207 Beta) | Gallery

Main article | Scripts (Sonic, Tails, Knuckles, Amy, Big, Gamma, Super Sonic) | Staff | Glitches | Beta elements | Gallery | Re-releases (DX, 2010)

Main article | Staff | Glitches | Beta elements | Gallery | Re-releases (Plus)