Debug Mode is the general name for a category of video game features designed to assist game developers in testing and debugging their video game's code. For instance, a menu that allows the user to edit level layouts or test object's functionality may be described as Debug Mode. With the requirement of the console's development kit, the Debug Mode is commonly utilized in the video game's development and it tends to be removed or hidden once the game is released, as it grants abilities beyond those intended for the player.
Concept and creation
The name "Debug Mode" originates from western publications and magazines covering Sonic the Hedgehog games, which described the cheat codes for unlocking the feature in the early 1990s. Later on, Sonic & Knuckles Collection and the Windows 95 version of Sonic the Hedgehog CD used the term "Debug Mode" in the games' internal coding. The name was later fully implemented in Sonic Mania and its expansion Sonic Mania Plus. Alternately, the name "Sonic Construction Set" is used to describe the feature in the Sonic the Hedgehog 1 & 2: Sega's Official Player's Guide book.
In Japan, earlier main game installments in the Sonic series used the term edit mode (エディットモード editto mōdo?) in the game's internal coding, which was described as such in magazine publications and strategy guide books. Sonic Jam is a rare example of the "edit mode" term being used in western releases, as it was included in the Secret Card's cheat code list in the Sonic World feature.
Sonic the Hedgehog (1991), 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 coordinates of the player's location in place of the score counter. The player may then activate and deactivate object placement mode, which replaces the player character with an item that can be freely moved around the stage with and can cycle through the list of placeable objects before placing them onto the level. 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. Although each game's Debug Mode shares the same basic controls, there are also slight differences between each.
Examples of Debug Mode in action
The installments in the Sonic the Hedgehog series have specific cheat codes to activate Debug Mode without using hacks or cheat cartridges (such as GameShark) are mentioned here.
Sonic the Hedgehog (1991)
To enable Debug Mode in Sonic the Hedgehog (1991), at the title screen, press ↑ ↓ ← → . If done correctly, a Ring chime will play and pressing Start while holding will begin the game with Debug Mode. In revisions of the game, the first part of the method is changed to ↑ ↓ ↓ ↓ ← → if played on a Japanese console.
In the Sega Mega Drive version, the player may press to activate and deactivate object placement mode, which replaces the player character with an item that can be freely moved around the stage with and placed by pressing . Pressing will cycle through placeable objects, and while holding , pressing the button will cycle backwards through the list of objects. While the game is paused, pressing will return to the title screen, holding will cause the game to run at half speed, and will advance the game by one frame.
In this game only, 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 the 2013 remaster, Debug Mode can be enabled while at the Level Select Sound Test by playing 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 object placement 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 object placement mode, the player must tap the HUD again.
Sonic the Hedgehog 2
Debug Mode is featured once again in Sonic the Hedgehog 2. To enable Debug Mode, 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 on the Level Select's Sound Test. Then, select a Zone, hold , and press Start.
In the Sega Mega Drive version, the Debug Mode features and controls remain identical to those for the original Sonic the Hedgehog. Only the main playable character controlled by the first player can enter object placement mode, Tails is not able to enter object placement if he is following Sonic. There is an additional feature that can be enabled as well; "Night Mode" may be activated by holding while entering a Zone from the Level Select. This highlights foreground sprites and darkens background sprites.
In the 2013 remaster, Debug Mode can be activated by having the player playing the same music tracks as the original release in the Sound Test. The controls remain the same from the 2013 remaster of the original Sonic the Hedgehog and in addition, the player can return to the Level Select anytime while in object placement mode by tapping the lives counter at the top right corner of the screen.
In 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 down, while one of the acts is highlighted in the game and press start to commence the game with Debug Mode enabled.
Sonic the Hedgehog CD
- Sega CD version: 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 Start. 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.
- Windows 95 version: 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].
- 2011 re-release: First unlock the Sound Test. As in the Windows 95 version of the game, 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 enable Level Select and head to the Level Select screen. Here the player has to hold down, select one of Zone 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 chime will be heard. Following this, pause the game and press to go back to the title screen and then head to 1 Player or Level Select. There, select a Zone, hold 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 the 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.
The Debug Mode in all three games remains similar to that of Sonic the Hedgehog 2. The controls for Debug Mode are as follows:
|Enter/exit Debug Mode|
|Activate Debug Mode >||Cycle through object selection|
|Activate Debug Mode > Hold +||Cycle through object selection backwards|
|Activate Debug Mode >||Place objects|
|Hold +||Cycle through the playable character's sprites|
The game's HUD no longer shows the character's location coordinates continuously when the player deactivates object placement mode, which is also apparent in the future games (including the remasters of the previous Sonic games). In Sonic the Hedgehog 3 & Knuckles, enabling Debug Mode will also allow any character to play all Acts, including Acts they are not intended to play through normally (such as Sonic/Tails in Knuckles' version of Sky Sanctuary Zone and vice-versa).
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. Below is a 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 , then using to move around.
- 0, 2, 1, 5, 6, 6: Gives the option to skip to the next stage by pressing down on the .
- 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, Debug Mode is an unlockable feature which is enabled by obtaining at least sixteen Medallions from the Bonus Stages. 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 // + //, 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 // to access the Debug Mode in-game. However, this cheat code was patched out as of Version 1.03.
Below is a list of controls for Debug Mode in each platform:
|Enter/exit object placement mode|
|Cycle through object selection (forwards)|
|Hold >||Hold >||Hold >||Cycle through object selection (backwards)|
|Cycle through Monitor power-ups (if the Monitor is currently selected)|
|Place currently selected object|
In gameplay, once object placement mode has been activated in an Act and that Act is later finished (even through normal means), there are no transition cutscenes to the next Act unless if the player visits a Special Stage, Bonus Stage or Pinball Stage.
In Sonic Origins, Debug Mode is an unlockable cheat code feature in Sonic the Hedgehog 3 & Knuckles. To enable Debug Mode, the player must, at the Sound Test, play sounds 01, 09, 09, 04, 01, 00, 01, and 08. A Ring chime will then sound to confirm the code. From there, the player can select any Zone to start it with Debug Mode. The following commands for this game's Debug Mode are as follows:
- Enter/exit object placement mode: Press //. Also, while in object placement mode, use the Left Stick, , or Arrow Keys to move around.
- Cycle forward through available objects: Press //.
- Cycle backwards through available objects: Press // while holding //.
- Change item subtype when selecting item: Press //.
- Place selected item: Press //.
- Reverse gravity when outside object placement mode: Press //.
While Debug Mode is active, the camera coordinates will be showcased by the top line of hex digits in the top-right corner of the screen. Player coordinates, on the other hand, are showcased by the bottom line of hex digits in the top-right corner of the screen.
- 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 remaster of the original Sonic the Hedgehog, playing songs in the Sound Test for activating Debug Mode can format 23 June 1991. This is the release date of the original Sega Mega Drive version of the game in United States and Europe.
- The cancelled Sega Saturn game Sonic X-treme also features a Debug Mode in the 714 build. It is activated by pressing Start and then . Unlike other games, it is available from the start and it cannot be exited. The only object the player can place is a Ring, which is done by pressing Start then .
- 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.
- "S.W.A.T. - Sonic The Hedgehog (Genesis)". GamePro (IDG Communications) (29): 133. December 1991. "To reach a Debug Mode that enables you to pull some strange tricks with your game wait for the title screen to appear and then press Up, Button C, Down, Button C, Left, Button C, Right, and Button C on Controller 1. Next, simultaneously press Start and Button A until your game begins. Now press Button B to enter the Debug Mode. Use Button A to select objects, and Button C to place them."
- "PG Tips: Sonic the Hedgehog". Game Zone (Dennis Publishing) (3): 71. 18 December 1991. ISBN 9770964466006-03.
- "Tips: Sonic the Hedgehog". Mean Machines (EMAP) (16): 71. 27 December 1991. ISBN 9770960495000-01. "Press B to get into the DEBUG mode. Press A to change the sonic character into another and press C to put this onto the playfield. Funnily enough, Sonic is totally invulnerable on this playing mode too."
- "Megadrive Tips - Sonic the Hedgehog". Mean Machines Sega (EMAP) (9): 38. 25 May 1993. ISBN 9770967901016-07.
- "The Complete Sonic Tips Guide". Mean Machines Sega (EMAP) (30): 47. 28 February 1995. ISBN 9770967901016-04.
- "Ultra Top Secrets". Sonic the Hedgehog 1 & 2: Sega's Official Player's Guide. Compute; Expanded edition. 1993. p. 62. ISBN 1-55958-335-5.
- "ソニックジャムコマンド集" (in Japanese). ソニックジャム オフィシャルガイド. SoftBank. 2 October 1997. p. 114. ISBN 978-4797303377. "同じようにタイトル画面で下のコマンドを入力すると、ソニックが無敵になる。 ただし落下や圧死には無効だ。 エディットモードは、 Bボタンでソニックを別のキャラクター(リングなど)に変え、 Cボタンで画面上に配置するモードだ。"
- "隠しコマンド一覧表" (in Japanese). ソニックメガコレクション最強攻略ガイド. Shogakukan. 1 March 2003. p. 56. ISBN 978-4091060907.
- Sonic Team (22 August 1997). Sonic Jam. Sega Saturn. Sega. Area/Level: Sonic World. "Secret Card: Code-2 - Sonic the Hedgehog - Invincible & Edit / <During Game> B : Edit mode on/off A : Turn into the other characters C : Put character on field"