Sonic & Knuckles (prototype 0525)

From Sonic Retro


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Sonic & Knuckles (prototype 0525)
Publisher: Sega
System(s): Sega Mega Drive
Genre: Action

Sonic & Knuckles Prototype 0525 for the Sega Mega Drive was released by drx during the February 23rd, 2008 proto release. This prototype differs from the other Sonic & Knuckles prototypes in that it is already locked-on to Sonic 3 (final version). By itself, this prototype will not boot. A savestate (info) (21 kB) has been produced that allows the game to be played alone, but it is very "broken"; the level art doesn't load correctly, any type of boss (including Knuckles at Hidden Palace) will crash the game, badniks do not appear (but still function correctly), and the list goes on.

Download.svg Download Sonic & Knuckles (prototype 0525)
File: Sonic & Knuckles (Prototype 0525 - May 25, 1994, 15.28) ( (2.41 MB) (info)

Cheat Codes

  • Level Select: Enabled by default. Just scroll down on the title screen and select "Sound Test".
  • Debug Mode: Debug is enabled by default. Just hold A while selecting a level on the Level Select screen. The ring counter will be replaced with a player sprite/frame counter.
  • All Chaos Emeralds: At the sound test screen, play songs 02, 04, 06, 08.

Various differences

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  • The "& KNUCKLES" additions to the title screen and level title cards have not been implemented.
  • The save files on the Data Select screen have been lengthened downward to accommodate for the life and continue counters which have yet to be implemented, but not upward. The selection cursor hasn't been resized yet.
  • The Data Select screen does not record Chaos/Super Emerald data correctly.
  • Knuckles is not selectable from the save data screen: he is usually only available in level select, but can also be accessed by loading a save (e.g. from the final) which already has a Knuckles save, however it must be in the third slot or later, as this prototype only has six save slots, as per Sonic 3 alone.
  • In addition to only having six save slots, lives and continues are not saved. However, game progress is now tracked beyond Launch Base Zone.
  • When debug mode is active, the debug counters are always shown, unlike in Sonic 3C 0408 and Sonic 3 & Knuckles when they are only shown when in object placement mode. The timer displays the number of on-screen sprites.
  • Debug causes all sorts of graphical glitches, such as at Sonic staying as a garbled up monitor after changing back, which goes away when completing an act.
  • The "S" monitor makes the characters take their Hyper form like in Sonic 3 & Knuckles, rather than Super as in Sonic 3 alone and Sonic 3C 0408.
  • Super forms accessed with the Chaos Emeralds still seem to act like incomplete versions of Hyper forms like in Sonic 3C 0517:
    • Super Sonic uses Hyper Sonic's rainbow palette and also gets the dash attack, but doesn't get the star effect around his body or the flash and sparks when the dash attack is performed. He doesn't get the ability to breathe underwater, either.
    • Interestingly, Tails is able to achieve a Super form with only the Chaos Emeralds, but he doesn't get Super Flickies or the trailing sparks. However, using an "S" monitor will give Super Tails the Flickies (perhaps there was a Super and Hyper version of Tails planned at one point).
    • For Super Knuckles, he gets the ability to set off earthquakes by latching onto walls at high speed, but the trailing sparks aren't replaced with afterimages. He cannot breathe underwater, either.
  • Hyper Sonic's stars around his body are still completely different than in the final and has no afterimages. Hyper Knuckles has afterimages, though.
  • Unlike in final versions, if the "S" monitor is used with Knuckles, Hyper Knuckles WILL cause an earthquake when gliding for a distance into a wall.
  • Pressing A while the game is paused returns you to the level select screen rather than the SEGA logo screen.
  • On a Japanese system, the trademark symbols are not removed from the SEGA logo and title screen, and Tails' life counter does not become "Miles" even though the results tally changes to "Miles".


  • The exclusive Sonic & Knuckles themes have not been fully implemented, so some tracks still use their Sonic 3 variants:
  • Title Screen - Sonic & Knuckles
  • Invincibility - Sonic 3
  • Knuckles' Theme - Sonic 3
  • Act 1 Boss - Sonic 3
  • Extra Life- Sonic & Knuckles
  • Credits - Sonic & Knuckles (though the sting at at the end is from Sonic 3)
  • All Clear - Sonic & Knuckles
  • The Data Select music bug from Sonic 3 alone is still there.
  • The Title Screen theme is an earlier version with a slightly different end.
  • Although the "Game Clear" jingle is the Sonic & Knuckles version, it's actually an earlier version of the tune. Though the pitch is lower, the melody sounds pretty much identical up to the final note, but the timing for that note is very different and there's no background jingle echoing off afterwards like in the final version. Sonic & Knuckles final has a version of the Game Clear jingle as well as sound 32 on the Sound Test menu.
  • The actual credits music (now located as sound DC on the Sound Test menu), however, uses the extended Sonic 3 Game Clear jingle at the end of the song from the Sonic 3C 0517 prototype. The entire song before that is the same medley used in the final version of Sonic & Knuckles.

Zone Differences

Angel Island Zone

  • Act 1 will still play Act 2 music when returning from a Bonus Stage after the Zone has been set on fire, like in Sonic 3.

Hydrocity Zone

  • The Screw Mobile's twister can still glitch out Super/Hyper Sonic like it did in Sonic 3.

Marble Garden Zone

  • The Act 1 miniboss crash glitch from Sonic 3 that can be achieved with a second player is still present.

Carnival Night Zone

  • In this build, the Act 1 and Act 2 tracks are switched. They are switched in the sound test, too.
  • Knuckles does not run in at the start of Act 1.
  • When playing as Sonic alone in Act 1, Tails randomly appears after the boss. (This glitch randomly happens in the completed Sonic 3 but with a different frequency in which it happens)

IceCap Zone

  • In this build, the Act 1 and Act 2 tracks are switched. They are switched in the sound test, too.
  • Tails still has the snowboard graphics problem from the Sonic 3C prototypes. The snowboard intro overwrites Tails' tiles with the snowboard's, and when the snowboard disappears, Tails' tiles should load. However, Tails' AI doesn't allow this to happen fast enough, and thus proceeds to draw Tails with some of the snowboard's tiles still remaining. Only when Tails lands does the tile swap complete, and Tails return to normal.
  • The floating icicle spheres in one of Knuckles' routes can still hurt you when in Super/Hyper form.

Launch Base Zone

  • In this build, the Act 1 and Act 2 tracks are switched. They are switched in the sound test, too.
  • As soon as Knuckles defeats one of the Twin Hammers, the normal Act 1 theme resumes while the other Twin Hammer is still alive. If you are Super/Hyper Knuckles, defeating one of the Twin Hammers will cause you to revert to normal and play the regular Act 1 music, as if both were defeated.
  • Knuckles still doesn't fight the Big Arm at the end of Act 2, and the boss music does not stop playing when the Prison Egg appears.

Mushroom Hill Zone

  • Sonic and Tails' intro to Act 1 still hasn't been implemented yet; they begin standing in mid-air and simply fall to the ground.
  • Knuckles' intro isn't implemented at the right time. He falls from the sky normally, then when reaching the first set of breakable walls, the S&K Knuckles intro starts playing in that location, but with a miscolored bomb and no boss music. After the intro is over you start the level again, but Knuckles falls in his standing sprite and you can go through the level normally.
  • The Act 2 boss's starting position is shifted to the left slightly from the final. This allows you to score endless hits on the boss without destroying the satellite, and the battle won't start until you hit the satellite itself, thus it was changed in the final so the player cannot do this. Unlike in Sonic 3C 0408, the first 7 hits on the boss will count towards defeating it after destroying the satellite.
  • The boss does not explode when killed until he crashes into the tree.

Flying Battery Zone

  • The echo track of Act 1's music still goes off-sync after looping, and will slowly drag more and more behind the lead melody as it continues to play.

Sandopolis Zone

  • Your character does not fall under the sand and pop back out when Act 1 begins; he merely falls from the sky and lands on the ground normally. Likewise, your controls are not locked, so you can move once the Act begins.

Lava Reef Zone

  • Knuckles does not run in at the start of Act 1, and there is a pile of rocks behind his starting position.
  • Shields do not protect you from the debris of the Iwamodokis.
  • The palette for the foreground rocks changes too soon during the Act transition in this build. However, the lava now cools like it does in the final.
  • Act 2 doesn't have the screen locked at the start of the level when accessed from level select as it does in the final. The lava is not cooled off at the start (even though it cools when transitioning from Act 1), but the zone uses the same blue palette as the final at this stage in development.
  • When you encounter Knuckles, his theme doesn't play, and he laughs after punching the boulder at you. The boulder won't cancel your Super/Hyper form.
  • The Act 2 boss area still doesn't play the boss music until you reach the boss.
  • Various sound effects are still missing.
  • The lava and sinking magma waterfall platforms in the Act 2 boss area have different animations.
  • After defeating the Act 2 boss, the lava appears to cool after the results tally goes away, but the heat shimmers remain and the lava can still hurt/kill you. You still need to jump across platforms to reach Hidden Palace like in the Sonic 3C prototypes.

Hidden Palace Zone

  • Hidden Palace still has Sky Sanctuary music.
  • The secret monitor stash still contains an "S" monitor instead of Speed Shoes like the final.
  • There is still a Fire Shield next to the teleporter that takes you up to Knuckles, instead of the Super Ring that's there in the final.
  • Knuckles' boss fight still plays the Sonic 3 miniboss theme and still continues to play through the Master Emerald theft scene after Knuckles is defeated.
  • If fighting Knuckles as Super/Hyper Sonic, Knuckles won't take damage when standing next to him. You have to actually jump on him to register a hit. Sonic doesn't take damage from Knuckles' punches when Super/Hyper.
  • Beating Knuckles still doesn't cancel your Super/Hyper form.
  • When Knuckles is stopping Dr. Eggman, Sonic can't move at all there whereas Tails can. In the final, you can whack Eggman as much as you like (not that it helps).
  • The animation order for Knuckles punching the wall before the teleporter is different. He gestures for Sonic to follow after hitting the wall, instead of before.
  • You cannot control Tails in Hidden Palace after Knuckles is defeated.
  • Hidden Palace when accessed by a giant ring still has a number of differences from Sonic 3C 0517:
    • Death Egg Act 2 music plays (this is due to it coming right after the Death Egg Final Boss level slot in the game).
    • The intro plays every time you enter the chamber.
    • The greyed-out Super Emerald locations don't save after you leave (They reappear after the intro).
    • The laser zaps all the Super Emerald altars even if you already have that Emerald (Although it still shows that you have that Emerald).
    • There are color differences in the prototype, probably changed so they could correspond with the colors of the Chaos Emeralds.

Sky Sanctuary Zone

  • After the Metropolis Zone boss has been defeated, the balloons don't pop until they reach the ground.
  • Mecha Sonic will appear again if you use a star post and fall down to one of the areas where he appears, even if he was already defeated there.
  • After defeating Mecha Sonic at the end of Sonic/Tails' Act, the results tally now appears, but Sonic and Tails won't do their victory poses and can still be controlled. Afterwards, the game cuts straight to Death Egg Zone without a cutscene.
  • Knuckles' Act now has the teleporter, but no rings.
  • If Knuckles' Act has been cleared and he has 0-13 emeralds, whatever ending (good or bad based on the collected Emeralds) will occur, no credits will appear, and the Sonic the Hedgehog 3 logo appears after Angel Island floats to its desired location rather than a Sonic the Hedgehog 3 & Knuckles logo.
    • If the ending is the "good" one, Knuckles will not jump out to the screen unlike the final version.
  • If one modifies a savestate so that it contains all 14 Emeralds, and clears Act 2 as Knuckles, a Sonic the Hedgehog 3 & Knuckles-esque ending occurs, with Knuckles, Sonic, and Tails all congratulating you. However, they again stand in front of a Sonic the Hedgehog 3 logo instead of a Sonic the Hedgehog 3 & Knuckles logo.

Death Egg Zone

  • The player does not run in at the beginning.
  • The overscan border color for Act 1 is red, instead of black like the other zones.
  • The light beam transportation systems have a slightly different countdown tick. It's four low tones, instead of three low tones and one high tone.
  • The final boss music still doesn't play. DEZ Act 2's theme just continues to play.
  • If Death Egg's final boss is defeated while it's firing its laser, the laser stays on screen while it explodes.
  • After the final boss machine collapses completely, everything stops rumbling.
  • The final chase is slower, and Eggman comes back on screen more slowly.
  • After defeating Eggman during the final chase, the HUD turns green. This is because the game has loaded Knuckles' 1P palette into the Knuckles CP palette slot.
  • After clearing the final Death Egg Zone boss, the game attempts to enter Sonic 3's credits sequence, as was the case with the 0517 prototype of Sonic 3C. However, the screen mode for this sequence no longer exists, so the game softlocks.

The Doomsday Zone

  • Automatically starts as Hyper Sonic when accessed via level select, unlike the final where you are Super Sonic if accessed in this way.
  • The background palette for The Doomsday Zone is the same as DEZ2's.
  • Various sound effects are still missing.
  • The zone scrolls a lot more slowly to begin with. You can speed up the scrolling by holding Right to gradually accelerate it, but hitting an asteroid will slow it down again.
  • There are a lot more asteroids at the start and a lot more missiles before reaching Eggman.
  • There are still lots of rings before reaching Eggman, as there are still no rings during the final chase.
  • When the boss reappears after its blue armour is destroyed the 'badnik popped' sound effect plays instead of the sound played in the final.
  • The latter half of Doomsday has no rings and asteroids and the projectiles Eggman fires have different graphics, especially the underneath weaponry.
  • When you hit Robotnik while chasing him, you don't get knocked back like you do in the final.
  • When The Doomsday Zone is cleared, the game goes back to the Level Select.

Bonus Stages

Bonus Stage access is now like in the final version of Sonic 3 & Knuckles, complete with color-coded stars, but with some differences:

  • 10-29 rings are required for the Slot Machine instead of 20-34 rings.
  • 30-49 rings are required for Glowing Spheres instead of 35-49 rings.
  • Once your ring count is past 50, Bonus Stage rotation will not reset, so you will always get the Gumball Machine.

Glowing Spheres

  • The Glowing Spheres stage still has a different layout, but is now less cluttered than in Sonic 3C 0517.
  • Items in the Glowing Spheres stage still drop instead of rising.
  • The score and timer are still not hidden in the Glowing Spheres stage.
  • Sound effects are still missing in the Glowing Spheres stage.
  • When playing as Sonic & Tails together in the Glowing Spheres stage, you will be kicked out if Tails dies, but this will only happen when using Debug Mode, though. This did not happen in Sonic 3C 0517.

Slot Machine

  • The Slot Machine bonus stage has the same layout from Sonic 3C 0517, but with less rings.
  • The background in the Slot Machine stage is still completely static (the little objects don't rotate and nothing scrolls).

Special Stages

  • Like in Sonic 3C 0517, if the player has all the Chaos Emeralds, they will not warp to Hidden Palace and instead receive 50 rings.
  • The Super Emerald Special Stages are now closer to the Sonic & Knuckles final, but their order is shuffled around a bit, and they still use the Sonic 3 Special Stage palettes:
    • Super Emerald stage #1 in this build is the same as Super Emerald stage #2 in Sonic & Knuckles final.
    • Super Emerald stage #2 in this build is an earlier version of Super Emerald stage #1 in Sonic & Knuckles final. Some of the blue spheres would be replaced with bumpers later on.
    • Super Emerald stage #3 in this build is an earlier version of Super Emerald stage #3 in Sonic & Knuckles final.
    • Super Emerald stage #4 in this build is Super Emerald stage #6 in Sonic & Knuckles final.
    • Super Emerald stage #5 in this build is Super Emerald stage #4 in Sonic & Knuckles final.
    • Super Emerald stage #6 in this build is Super Emerald stage #5 in Sonic & Knuckles final, though two blue spheres are yellow spheres in this version.
    • Super Emerald stage #7 in this build is an earlier version of Super Emerald stage #7 in Sonic & Knuckles final, with differences noticeable around the beginning.
    • Super Emerald stage #8 is the same as in Sonic & Knuckles final.

External Links

Sonic Retro
Sonic Retro discussion thread

Sonic & Knuckles
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Main page (Blue Sphere|KiS2|S3&K)
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Hacking guide