Sonic: The One Ring

Sonic: The One Ring is a gameplay hack that I made of Sonic the Hedgehog for the Sega Genesis/Mega Drive.

It's a fairly simple hack, with the original music, palettes, and layouts (largely) intact, because it was meant to be a simple project, and is intended to be the same Sonic the Hedgehog that players are familiar with, but with a special twist to the gameplay.

That twist is to make the game into a sort of scavenger hunt. Each Zone and Special Stage has had all of its Rings removed, except for one that is cleverly hidden: the One Ring. Sonic must find the Ring, collect it, and carry it to the end of the level without losing it in order to progress. If Sonic loses the Ring, he'll lose one life and have to start over.

Without the One Ring in hand, the Signpost, Giant Ring, and Robotnik won't appear at the end of the level. Don't worry, though - Sonic can go back and continue his search. The addition of the Spindash, as well as some minor layout tweaks, allow Sonic to backtrack through the Zones.

Watch the trailer for more details:

Download the ROM (revision #10)


  • Random Item Monitors

    Of course, there can't be any Super Ring Monitors; there is only One Ring, after all! Therefore all of them are replaced with these, Random Item Monitors (other Monitors remain intact; the Shields and 1-Ups you expect will still be where they were).

    Destroying them will give you one of these items:

    • Shield
    • Invincibility
    • Speed Up (Note: not present in Labyrinth Zone or Scrap Brain Act 3)
    • 1-Up
    • Extra Time

    The Extra Time monitor is new to this hack; it awards Sonic 20 extra seconds on the clock. This can be useful if you spend too much time searching for the elusive Ring.

    PROTIP: The Random Item Monitors aren't truly random - they give out items based on a secret condition. Experiment to see if you can learn how to reliably get the item you want. No, it doesn't take sending vibes!

  • Modified Lamp Posts

    Normally in Sonic the Hedgehog, passing a Lamp Post will activate it along with all of the others that are "earlier" in the level. However, in The One Ring, Sonic might be doing a lot of backtracking. So the Lamp Posts have been changed - passing one will change all others back blue. Then they can be passed once more to record your position again.

    (There are also a few more Lamp Posts than usual; I added some to Starlight, Spring Yard, and Scrap Brain, because they didn't have enough to be fair with the added challenge that having no Rings for most of the time brings.)

  • Shield Hoarding

    If Sonic is already wearing a Shield when he destroys a Shield Monitor, he'll now get another Shield, protecting him from one more hit. This is an important feature - try to get as many Shields as possible, because without Rings they'll be your best way to survive.

    When Sonic has at least one Shield in reserve, the Reserve Shield Icon will appear next to the Life Counter.

  • Infinite Continues

    Sonic now has infinite continues. As long as you opt to keep going, you'll never be sent back to the title screen when you run out of lives.

  • Extra Special Stage Chances

    There are now two extra chances to enter the Special Stage and collect the Chaos Emeralds, because Giant Rings have been added to both Acts of Scrap Brain, which used to lack them.

    (I'm guessing this is because the dynamic smoke art and Dr Robotnik animation overwrote the Giant Ring art in VRAM. With a little creative shuffling, I was able to avoid tile conflicts and add the Giant Rings in.)

  • The Spin Dash

    Sonic's signature move from Sonic the Hedgehog 2 is present and accounted for. By now, it's a staple of the hacking scene. It works a little differently though - because super-high launch speeds are necessary for some of the backtracking, the Spin Dash no longer winds down when you let go of the Jump Button. Simply tap it a few times to charge up to maximum, and release the D-Pad to go rocketing forward.

  • Modified Special Stage Behaviour

    If you fail a Special Stage, it will no longer progress to the next one. This allows you to try each stage over and over until you get it, without forgetting the practice you've accumulated. (Sonic the Hedgehog 2 works this way, which was my inspiration.)

    Also, the Giant Rings will continue to appear, even after you've collected the whole set of Emeralds. At that point, instead of awarding you with Emeralds, the Special Stages will contain special 3-Ups. (Sonic 3D Blast does something like this, which was also my inspiration.)

  • Ring Sense

    Sonic has a second new ability besides the Spin Dash. By looking up or down, he can "listen" for the hidden Ring. If it's near enough, it will chime if it's below him when he looks down, and chime if it's above him if he looks up. It's also stereo mixed, so you can tell whether the Ring is behind or ahead of Sonic, as well.

    (Note: The Ring Sense only pays attention to the Ring's horizontal proximity to Sonic. If you hear the chime, it could be anywhere in that vertical "slice" of the level. Use looking up and down to narrow your search.)

  • SRAM Save Support

    The game will now automatically save your progress with the completion of each Act or Special Stage. If you wish to start a new game, simply choose "Clear Data" at the Title Screen instead of "Play Game".

    This verges on braggadocio, but I have to point out again that the Title Screen reflects Sonic's progress throughout the Zones and Acts, even though it's in the Trailer. It's probably my favourite achievement with this hack, because it's both technical and artistic. It's also totally unnecessary, and I did it just to prove I could, which is what makes it so fun.


I went through very little effort to combat cheaters with this hack. (Though I did change the Level Select code to D, R, R, U, L, L just to liven up their lives a bit.) This is because, with the Sonic hacking community, where there's a hedgehog, there's a way.

There are many ways to cheat to find the Ring, most of which are nigh impossible to combat. For instance, anyone can make a savestate, and search the OST space for the Ring Object ID, and then read its X and Y coordinates. You can't pull one over on Sonic hackers, so I won't even bother.

The point of the hack is to have fun exploring the familiar Zones, to see them with new eyes and challenge yourself. If you get stuck and it ceases to be fun, then I'm not gonna begrudge anyone a few shenanigans to get ahead.

If cheating isn't your style, and you want some honest help finding the Ring, one thing you could do is visit Zone: 0, a really nice site with Player's Guides (complete with detailed maps) for most of the classic Sonic games.

It was Zone: 0's maps that I used to inspire me on the hiding places for the hack, so if you look them over you might get inspired on where to find them. You might also just enjoy yourself - they're expertly put together, and seeing the level design in toto is interesting, as well.


These are some of the people who have helped me out, majorly and minorly, with this hack. I can't possibly list them all; I've learned so much from so many, from reading archives and guides from all over. I found the SCHG: How-To's especially useful to practise my ASM with and familiarise myself with hacking, so thanks to the collective of characters who contribute there.

  • Selbi (Extra Time Monitor help)
  • nineko (Time/Rings Flashing Bug fix)
  • Cinossu, shobiz, Xkeeper, and Chilly Willy (SRAM help)
  • Bugfinders: Cinossu, Andlabs, nineko, Max Firestorm, NMMX, Neo, Ink, Rom, CrazyTerabyte
And a special thanks to Ell678 for playtesting! :)

"Let's Play" by 13th Nightmare (Horrormaniac13)

You know you've made it when your hack has a "Let's Play" on YouTube! =P (Or was that, 'you know you've made it when you've got a cameo in Futurama as a pickled head'? I forget, now...)

Seriously, though, it's a great playthrough. Of course it has spoilers as to the locations of the One Ring in each level (so you can use it as a hint guide, too, if you want).

Playlist with all 19 parts

Sonic's Super Hints

And, finally, because I love the cheesy US manuals for Sonic games, I've decided to add a few silly Super Hints for finding the One Ring, from Sonic himself. ;)

(They're in black so you have to select and/or copy them to see them. Use them well!)

  • How well do you know your Zones? Check the secret places and hidden rooms from the original game. You may find something there.
  • Sometimes it pays off to make a leap of faith.
  • There were a few areas I couldn't reach in the original. With my new Spindash, I might be able to make it this time.
  • Some regions may look like secret hiding places for the Ring, but don't assume you've found it that easily. They may just be helpful modifications to aid with backtracking.
  • Things aren't always as they seem. Just 'cos it looks familiar, doesn't mean it won't do something new.
  • Listen closely. You might hear the Zone shifting around, or hear an object in a secret path you can't see.
  • Attention speedrunners! Some of the crazy tricks you used to pull off just for fun might be useful ways to access a path now.
  • The Ring isn't always visible. Break suspicious looking blocks.
  • Can the Ring move? Maybe if it was carried by something...
  • Programmers can be insufferable show-offs (the stories I could tell about my pop, Yuji...) Sometimes the Ring is hidden in a way just to showcase some coding achievement.
  • Keep an eye on the enemies. Do some look a little different? Might some even be friendly?
  • I made a pretty weird discovery in the past on the Little Planet - a Ring Shrine! I wonder if it was the only one...
  • Remember to use my "Ring Sense" ability if you get really stuck!

Well, I hope you enjoy the hack! ^_^

Download the ROM (revision #10)

Other Changes

For anyone with curiosity as to what all else I've changed in the hack, here's the exhaustive list.


  • Scrap Brain chutes now require button press to activate, and work both ways
  • Scrap Brain "50 Ring" chute now requires "up" to be pressed instead
  • Changed Level Select code to automatically activate slomo and debug cheats, too
  • Changed Level Select code to Down, Right, Right, Up, Left, Left
  • Altered Green Hill tunnels to function more like Sonic CD's
  • Scrap Brain doors don't close unless Ring is collected (to aid in retraversal)
  • Altered Spring Yard Spikeball Chains to rotate anticlockwise when moving left
  • Made the jumping from a roll work like Sonic CD and still be controllable
  • Made the Ring object not load if you already have it from respawning at a Lamp Post with it
  • Added Lamp Posts to the Zones that lacked them, to make things a bit easier
  • Added a bunch of Zone agnostic objects (see topic for details)
  • Altered Orbinauts in SLZ so that they throw their spikeballs like the ones in LZ/SBZ3
  • Made Newtrons destructible while they're falling
  • Made all SLZ staircases able to be knocked down from below and pushed down from above
  • Altered Jawz so that they lower with the water level
  • Made Rings bounce when they hit the bottom Zone boundary, to make the Spring Yard boss more fair
  • Made Sonic's collision mask shorter when he ducks, as when he rolls.

(...and a bunch of other object stuff that might spoil the hidden Rings if I mentioned it! =P )


  • Added Sonic's shoe stripe to the sprites that were missing it
  • Added "The One Ring" subtitle to Title Screen, by modifying "Press Start Button" object (used guide)
  • Fixed a backward spring in GHZ act 2
  • Made lost Ring flash when almost gone
  • Added Sonic CD four-frame balancing animations, forward and backward
  • Raised some of the Signposts that were stuck too low in the ground
  • Changed some of the Demos so that Sonic wouldn't die (the removal of the speed cap changed the timing)


(Note: I'm not listing all the bugs of my own that I had to fix; this is a list of bugs I fixed that either the original had, or that are caused by the additions such as the Spindash.)

  • Fixed the "walking jump" bug for normal solids and monitors (used guide)
  • Fixed spike "bug" (used guide)
  • Fixed hidden bonuses bug (used guide)
  • Fixed Horizontal Control Lock bug; it now clears when Sonic jumps
  • Increased speed threshold for rolling to make ducking for Spindash easier
  • Fixed Spike sound effect to match Sonic 2's method
  • Fixed bug with persistent dust trail when drowning while Spindashing
  • Fixed "walking drown" bug when drowning near a solid object
  • Fixed a multitude of camera scroll problems caused by retraversal capability
  • Fixed TIME not flashing red when over 9:00 if Ring was got
  • Fixed Roller Badnik PLC that caused garbled graphics
  • Removed "speed cap" for ground and air movement (didn't use the guide, as I didn't notice it at the time)
  • Fixed bug that caused the screen to go crazy after Sonic respawns from dying after releasing the Spindash
  • Fixed garbled Button graphics at beginning of SBZ3
  • Fixed garbled Spring graphics at beginning of SYZ2
  • Fixed problem with having Super Shoes at level end speeding up Act Clear music. Touching the Signpost now clears Super Shoes.
  • Fixed a problem with Spindashing at level start that caused a camera scrolling bug.
  • Fixed a bug with Spindashing into Caterkillers harming Sonic when it's not supposed to.
  • Fixed a bug with Spindashing into SLZ fans screwing up the camera.
  • Fixed a bug in Sonic's harmed routine that caused him to die if he went off the top of the screen.

If you want to make any of these changes or fix any of these bugs in your hack, feel free to email me - I'll be glad to send you my solutions (though I might not be so quick to reply, as I'm getting ever-increasingly busy these days). Eventually I hope to write up detailed guides for most of the changes, but if I don't get to it soon (which is likely), asking me directly is an acceptable option.


  1. I've been playing this hack for about an hour or so, and can safely say that I'm hooked!

    This is a great hack. Having to find just 1 ring to pass each ZONE and having to find 1 ring to pass the special stages is a really cool and innovative idea, and makes for very interesting gameplay.

    It's interesting to play the ZONEs you think you're used to, only to find alternate paths and layouts, sometimes leading to that all important ring!

    I love all of the neat additions, such as saving progress, the relevant background on the title screen which shows your progress, the Sonic CD 'edge of ground' animations, and the random item monitors.

    All in all, well done! :-D

  2. Anonymous06 July, 2010

    Awesome hack, absolutely love the concept. Feels like a different gave even. Random monitors make for a different experience every time! MUST TRY!

  3. Fantastic! Congratulations! This is the best hack I've ever seen before!

  4. Well you already know how I feel about it... seeing as I'm the first guy to do an LP of it on youtube.
    I love this hack. It is such a simple idea, but it works brilliantly. Especially when you know where the Ring is and then have to figure out how to get it.

  5. i'm stuck in star light zone. i killed all 3 enemies and the area with the ring didnt unlock

    i tried killing myself to reset the enemies and kill them again, but the area still didnt open...

  6. Thanks for letting me know, I'll see if I can't fix it.

  7. I finally fixed the bug in SLZ3, so a new revision (#10) is now up.

  8. Love the changes in the title screen reflecting your progress! Fantastic!

  9. I'm new to online sonic hacks and I'm having trouble trying to get this hack working because I don't know what program to open it with. If anyone could tell me that would be great.