Sonic the Hackable - Splash Hill Demo

By NyaNyaLily

Sonic the Hackable is a Sonic 4/Dimps styled Sonic ROM hack of the original Sonic the Hedgehog for the Mega Drive. It features new layouts, new zones, new moves and a remixed soundtrack by LackofTrack and others.


After Dr. Eggman's defeat in Sonic the Hedgehog 4: Episode II, the Death Egg MK II is left without a power source. Sonic, whose escape pod has landed back onto Mirage Island, is left without Tails, who seems to have landed somewhere else. Knowing Dr. Eggman's resilience, Sonic knows that the evil doctor will stop at nothing to find a new power source to breathe new life into his wicked contraption. With this in mind, Sonic storms off towards the Mad Gear, Eggman's power plant that was powerful enough to refurbish Metal Sonic. Eggman's true plans are unknown, but breaking into his base and destoying his only known source of power sounds like a good start to stop whatever it is.

Now, Sonic must travel through Mirage Island one final time to put an end to this saga once for all.


A/B/C - jump

A/B/C (midair) - air dash

Left/Right - move

Up - look up

Down - crouch

Down + A/B/C - spindash


Original Game: Sonic Team

Tools used

Sonic 1 GitHub disassembly: Hivebrain, Stealth, drx & Esreal

SonLVL: MainMemory

S1SSEdit: MainMemory

SonED2: Stealth

Tilemolester: SnowBro

Sonic One Music Editor: fuzzbuzz

Sonic 2 GitHub disassembly: Nemesis, Aurochs & Xenowhirl

NewNeko Palette Editor: Nineko

Music Pointer Fixer: Erik JS

SMPSConv: ValleyBell

SMPS research pack: ValleyBell

mid2smps: ValleyBell

Nineko Midi Event Editor: Nineko

The Sega Data Compressor: Magus

SonMapEd: Xenowhirl

Sonic 4 Episode I midi's rip: evilhamwizard

SMPS2ASM: flamewing

Ultimate Sega Hideki sample pack 3.1

gmv2bin: Mercury

Flex 2: snkenjoi

SonPLN: MainMemory

SMPS Optimiser: Valleybell






Guides used

Spindash Guide Part 1: Lightning & kram1024

Spindash Guide Part 2: Puto

Spindash Guide Part 3: shobiz

Spindash Guide Part 4: Mercury

Different songs per Act: nineko

Dynamic Palettes: PsychoSk8r

PAL Music Tempo Guide: Crash

Walk Jump Bug fix: Cinossu & Mercury

Spike Bug fix: FraGag

Fix the SEGA sound: Puto

Display Press Start Button Text: Quickman & Egor305

Water Guide: Tornado

How to make a good custom palette: Mr. Cat

SMPS Guide: Markeyjester

Use Dynamic Tilesets in Sonic 1: HPZMan (Only Dynamic Pattern Load Cues were used)

How to make a good sounding mid2smps conversion: A-S-H

Remove the speed cap: Tweaker & Puto

Fix Song Restoration Bugs in Sonic 1's Sound Driver: Markeyjester & Clownacy

Fix demo playback: FraGagFix the camera follow bug: MarkeyJester

Fix the HUD blinking: Quickman

Optimize ring scattering: SpirituInsanum

How to implement "Dimps ring physics" in Sonic 1: Shockwave

Fixing the top-right corner reloading glitch in S1: SpirituInsanum

How to record a demo: Mercury

Extend ROM Chunks to $FF in Sonic 1: GenesisDoes

How To: Reversing the Timer in Sonic 2 (ASM): DLloyd

How to optimize Shield Art loading in Sonic 1: SuperEgg

Adding Sonic 2's Splash and Skid Dust to Sonic 1: ProjectFM

Make an Alternative Title Screen: JcFerggy

(Sonic 1) Sonic CD Roll-Jump & Freeing a Status Bit: Kilo






Sonic Team

Level Design


SMPS Remixes

Splash Hill Act 1: LackofTrack

Splash Hill Act 3: LackofTrack

Sylvania Castle Act 1: LackofTrack

Sylvania Castle Act 2: LackofTrack

Sylvania Castle Act 3: LackofTrack

Casino Street Act 1: LackofTrack

Night Carnival Zone: CHRdutch

Metropolitan Highway: Dv2

Lost Labyrinth Act 1: LackofTrack

Lost Labyrinth Act 2: Spanner

Lost Labyrinth Act 3: LackofTrack

White Park Act 3: LackofTrack

Mad Gear Act 1: LackofTrack

Mad Gear Act 2: LackofTrack

Mad Gear Act 3: LackofTrack

Sonic 4 Boss Pinch: LackofTrack

Sonic 4 Invincibilty: LackofTrack

Sonic 4 Title Screen: LackofTrack

Sonic 4 Episode I Cutscene: LackofTrack

Sonic 4 Episode I Final Boss: LackofTrack

Sonic 4 Episode I Game clear: LackofTrack

DualPCM sounddriver by MarkeyJester




Sonic Team

Bug fixing support











Sonic Title Font: SEGA Enterprises

Meow Mix song (Used in SEGA sound)

Smosh (Used in SEGA sound)


File Type: rom/mega-drive

File Size: 522.69 KB

giovanni.gen @ 2021-10-11 13:15:02

I've always been a fan of Sonic the Hackable. The earlier versions have always had me astonished with the level design's quality. I did not notice major changes since the older versions, but I genuinely think Splash Hill looks splendid here. That's all I can say, though, since not much else has changed since the earlier versions. Can not wait to see the other zones' artistically revamped versions!

dilworks @ 2021-10-12 13:43:43

Sonic the Hackable always make me ponder if Sega should have released Sonic 4 on the Gen/MD instead of those newfangled "next-gen" platforms...

Superb job, too bad this is still a demo, because I want more~! (at least Level Select is still there...)

Jdpense @ 2021-10-12 22:03:46

I really love the art and improvements on this so far! Can't to see the full release!

Dima Cool @ 2021-10-13 01:04:54

Once I really wanted Sonic 4 on a mega drive, and you fulfilled this little dream. The demo is very colorful and fun, I'm really looking forward to the new version!

P.S. In level select, I saw your developments in future zones, and the question arose why the 3rd act of spring yeard Is music from Forces playing?

Leolaus @ 2021-11-15 10:22:42

probably a placeholder until a proper remix is made

NunofYerbizness @ 2021-10-15 03:15:24

For what it is so far, it's pretty good… Only things I could really comment on, that I think could be rectified in a future update are that Sonic's title screen sprites looks kinda unfinished, on terms of palette choice and overall shading work, not that it doesn't already look nice now… The other being that the main boss theme hasn't been replaced with the unused track from Sonic 3D Blast's 825 prototype yet.

But overall, this hack is still a decent marvel, even in its current state; At least an 8/10.

Animemaster222 @ 2021-10-16 12:18:18

As a Sonic 4 style sonic 1 hack it's pretty accurate, just with better physics. I guess the only thing would to add the homing attack. Good job so far, it captures Sonic 4 episode 1 pretty well. Just touch ups here and there.

JefferyTheNotepad @ 2021-10-16 15:03:51

Good level design, good gameplay, good visuals, and the cool little Homing Attack boost thingy was awesome too!

And it basically just made Sonic 4 into an actually good game. So props for that!

Winins0 @ 2021-10-23 01:39:25

Sonic 4 needs more love and this delivers that. Great hack!

metal_soniclol @ 2021-11-05 09:03:51

very cool but this is a demo and this is so sad but I hope you finish this hack

HruMan @ 2021-12-15 09:37:55

Wow, this hack has really, really improved since "A Generic Sonic 1 Hack"

As always, great job!

Iamkuk @ 2022-05-26 11:04:32

Good job)))

WoahAldo @ 2023-09-11 18:02:28

Played this back in the day,but a shame it ends on Splash Hill Act 3, it seems pretty unfinished but good nonetheless,nothing bad or wrong i saw on it,pretty solid rom hack for a contest

Hope it gets update furthermore some day