Download CDDA pak at: http://greenoasis.akawah.net/hacks/Sonic%201%20Character%20Pak%20CDDA%20Audio%20Pak.zip
Then put all the music files in the same folder as Sonic 1 Character Pak.cue

Rest of original readme as follows:
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Title:		Sonic 1: Character Pak
Author:		LuigiXHero
URL:		https://sonichacking.org/entries/expo2020/287
----------------------------------------------------------------

Hey look something totally original that has never been done before!
So why does this exist?
I wanted to finish one hack before I move on from Sonic hacking and what better then a character pak made up of like 3 of my old character hacks. Only one I shown off publically before is Luigi but every character hack been a thing one way or another for a while.
So what does this have exactly?
4 playable characters in Sonic the Hedgehog (1991) for the Sega Mega Drive Genesis Entertainment System. Being fan favorite Sonic characters: Classic Sonic, Modern Sonic, Link? and Luigi? Complete with stuff to make them stand out and with that tweaks and changes to some levels to make use of it, though don't expect too much from that.
Also there is super characters and while this is Sonic 1i'm not that evil. Therefore I used my magic powers to replace the lampposts with starposts giving you a ton more chances at the special stages. I think it might even be possible to get all of them by Marble Zone.
Along with that we have some nice delicious full soundtracks to select from including:
The Original STH Soundtrack: but with fixed drums... people like that right? This is intended for Classic Sonic
Alternate Sonic Soundtrack: Other Sonic songs throughout the series this is intended for Modern Sonic. (Marble Zone in this is the best track in the game, make sure you hear it)
Legend of Zelda Soundtrack: Pretty self explanitory and you wouldn't guess who this was for.
Super Mario Soundtrack: Music from that other company. This is for Green Mario.
Meme Soundtrack: Music that make you go haha. This was basically included since I like to do songs out of boredom and had them all anyways.
CD Soundtrack!: If you plug a Sega Mega CD into your Genesis Drive you can use it to play CD audio. I included a preset one to make it a proper thing but you can play whatever. Try popping in a random music CD!
Note: Sorry if some songs are not great, it's 2am pst on the day of the deadline and I still have like 9 songs to make.
Update: It's now 8am and I finished the hack!
Controls:
Don't worry about figuring out controls right away or anything, there is a optional tutorial level for each character to help teach you. But still included here for completion sake.
Common:

Up + A,B,C = Turn Super/Normal
Up + A = Enable/Disable Debug (Takes priority over super stuff)


Classic Sonic:

A, B, C = Jump
Down + A, B, C = Spindash
Up + A, B, C = Peelout


Modern Sonic:

C (Ground) = Jump
B (Ground) = Boost
A (Ground) = Nothing
Down + A, B, C (Ground) = Spindash
C (Midair) = Homing Attack
B (Midair) = Jump Dash/Midair Boost
A (Midair) = Stomp


Link:

A, B = Stab (Does different ones depending on standing or crouching)
C = Jump
Up, Down (Midair) = Upwards and downwards stabs


Luigi (3D style):

A = Long Jump
B, C = Jump
Down (Midair) = Butt Slam/Hip Drop
B, C (Water) = Swim

Full Credits:
  CREATOR
    LUIGIXHERO

  PROGRAMMING HELP
    DEVON

  AMPS
    AURORA*FIELDS

  DUAL PCM
    MARKEYJESTER

  GRAPHICS
    MODERN SONIC SPRITES
      MOD.GEN PROJECT TEAM
    LINK SPRITES
      GONZO
    LUIGI SPRITES
      KACHING720
    MODERN SPRING SPRITES
      DOLPHMAN
    MODERN MONITOR SPRITES
      MOD.GEN PROJECT TEAM
    RUSH HILL ZONE TILESET
      LUIGIXHERO AND BUBS COOPER
    RUSH HILL ZONE BACKGROUND
      LOONEYDUDE
    EXTENDED SONIC 1 CREDITS FONT
      FROM SONIC 1 2013 AND TOUCHED
      UP BY DEVON

  MUSIC
    SONG TITLE
    SOURCE
      ORIGINAL CREATOR
      MIDI CREATOR

    ORIGINAL SONIC 1 MUSIC
      MASATO NAKAMURA
    OVERWORLD 1
    FROM ADVENTURE ISLAND 2
      HUDSON SOFT
      JOE CORTEZ
      BINBOWIE
    OPTIONS AND EXTRAS
    FROM SONIC MEGA COLLECTION PLUS
      SEGA
      KING METEOR
    ANGEL ISLAND ZONE ACT 1
    FROM SONIC ADVANCE
      SEGA
    PYRAMID CAVE ZONE
    FROM SONIC ADVENTURE
      SEGA
      STARHUNTER 1
    RED HOT SKULL
    FROM SONIC ADVENTURE
      SEGA
      DEVON
    HARD TIMES REMIX
      THE JETZONS
      SAMANTHA
    MUSIC PLANT ZONE
    FROM SONIC ADVANCE 2
      SEGA
    CHEMICAL PLANT ZONE ACT 2 REMIX
      SEGA
      ZENKUSA
    WITH ME
    FROM SONIC AND THE BLACK KNIGHT
      CRUSH 40
      SHADROW
    CASINO PARADISE ZONE ACT 1
    FROM SONIC ADVANCE
      SEGA
    KNIGHT OF THE WINDS
    FROM SONIC AND THE BLACK KNIGHT
      CRUSH 40
      SHADROW
    ENDLESS POSSIBILITIES
    FROM SONIC UNLEASHED
      BOWLING FOR SOUP
      SHADROW
    INVINCIBILITY
    FROM SONIC CD USA
      SEGA
      OCTAL LIVERSHITE
    WHAT IM MADE OF
    FROM SONIC HEROES
      CRUSH 40
      SEAN BEE
    OVERWORLD THEME
    FROM ZELDA: A LINK TO THE PAST
      NINTENDO
    COLOR DUNGEON REMIX
    FROM ZELDA: LINKS AWAKENING DX
      NINTENDO
      ICYBORK
    HECC-TAN
    FROM LINK AND THE FACES OF EVIL
      NINTENDO
      TAHUTOA
    BALLAD OF THE WIND FISH DANCE REMIX
      NINTENDO
      DANIEL LAWRENCE
    Angel Teardrop - Song of Storms Remix
      NINTENDO
      HYLIAN HERO
    DARK WORLD
    FROM ZELDA: A LINK TO THE PAST
      NINTENDO
      SEAN JACKSON
    GANON BATTLE
    FROM ZELDA: ORACLE OF AGES
      NINTENDO
      FIREMARIO
    OCARINA OF TIME MUSIC
      NINTENDO
    BOSS BATTLE
    FROM ZELDA: A LINK TO THE PAST
      NINTENDO
      MARK JANSEN
    TITLE SCREEN
    FROM THE LEGEND OF ZELDA
      NINTENDO
      YADANIICHAN
    SUPER BELL HILL
    FROM SUPER MARIO 3D WORLD
      NINTENDO
      LU9
    WATER THEME
    FROM SUPER MARIO 64
      NINTENDO
    RUINS
    FROM SUPER MARIO LAND
      NINTENDO
      JOSEPH COLLINS
    HAPPY NIMONO
      THINKONEMORETIME
    MUSHROOM BRIDGE THEME
    FROM MARIO KART DS
      NINTENDO
    XNAUT FORTRESS
    FROM PAPER MARIO TTYD
      NINTENDO
      SWORDBOLT
    KOOPALING BOSS
    FROM SUPER MARIO BROS 3
      NINTENDO
      SAIYANFOX
    BOSS THEME
    FROM MARIO KART DS
      NINTENDO
    BONUS ROOM THEME
    FROM SUPER MARIO BROS. ALL-STARS
      NINTENDO
    STARMAN THEME
    FROM SUPER MARIO BROS.
      NINTENDO
    TITLE AND OVERWORLD THEMES
    FROM SUPER MARIO WORLD
      NINTENDO
    LEVEL CLEAR THEME
    FROM SUPER MARIO BROS. 2 USA
      NINTENDO
      ROBERT AARON EASON
    STARMAN REMIX
      NINTENDO
      THINKONEMORETIME
    STATUS SCREEN
    FROM SUPER MARIO ADVANCE 2
      NINTENDO
      PAPER LUIGI
    ENDING 
    FROM SUPER MARIO BROS 1
      NINTENDO
      JOHN ENGELMAN
    GREEN HILL ZONE 
    FROM SONIC FORCES
      SEGA
      PTKICKASS
    RUINS 
    FROM UNDERTALE
      TOBY FOX
      LU9
    HIP TO BE SQUARE
      HUEY LEWIS AND THE NEWS
    UNITY
      THEFATRAT
      SHINKONET
    WHAT IS LOVE
      HADDAWAY
    SCIENCE BLASTER
      SPELLINGPHAILER
      GABRIEL YANNI
    BLOODY TEARS
    FROM CASTLEVANIA II
      KONAMI
      NINEKO
    CRAWLING IN MY SKIN
      LINKIN PARK
    SONIC ELECTRONIC
      ARCADE
      SNNTAILS
    RUNNING IN THE 90S
      MAX COVERI
      ELITEDFISH
    MEGALOVANIA
      UNDERTALE
      FAKT13
    VICTORY
    FROM FINAL FANTASY
      SQUARE
    All-Stars
      SMASH MOUTH
      BINBOWIE
    LOBBY
    FROM KAHOOT
      KAHOOT
      TAILS 64
    RUNNING IN THE 90S
      MAX COVERI
      ELITEDFISH
    LISA FRANK 420 MODERN COMPUTE
      VEKTROID
      Nameless
    SEGA JINGLE
    FROM SEGA CD BIOS
      SEGA
    UNDERGROUND THEME  *UNUSED*
    FROM SUPER MARIO BROS. 1
      NINTENDO
    GREEN HILLS *UNUSED*
    FROM SONIC 2 GAME GEAR
      SEGA
      DARKMIND
    ROCK *UNUSED*
      THEEIGHTHBIT
    CRISIS CITY *UNUSED*
    FROM SONIC 06
      SEGA
      HEUPOW00
    STARRY NIGHT ZONE *UNUSED*
    FROM SONIC MEGAMIX
      LEILA WILSON *WOOFLE*
    OVERWORLD THEME *UNUSED*
    FROM ZELDA: LINKS AWAKENING
      NINTENDO

  INCLUDED CDDA MUSIC
    SPEEDING TOWARDS ADVENTURES
      SEGA
      OCREMIX
    AQUARIUM PARK ACT 3 REMASTERED
    FROM SONIC COLORS DS
      SEGA
    MARBLE ZONE MODERN REMIX
      SEGA
      KDJMUSIC111
    AT DAWN
    FROM SONIC ADVENTURE
      SEGA
    DILAPIDATED WAY
    FROM SONIC ADVENTURE
      SEGA
    ACT CLEAR AND RESULTS
    FROM SONIC THE HEDGEHOG 2006
      SEGA
    INVINCIBILITY
    FROM SONIC ADVENTURE
      SEGA
    TITLE SCREEN
    FROM SONIC GENERATIONS
      SEGA
    DROWNING
    FROM SONIC ADVENTURE
      SEGA
    FINAL BOSS
    FROM SONIC ADVENTURE
      SEGA
    REACH FOR THE STARS
    FROM SONIC COLOR
      SEGA
      CASH CASH
    BLUE SPHERES
    FROM SONIC AND KNUCKLES COLLECTION
      SEGA
    NO WAY?
    FROM SONIC AND KNUCKLES COLLECTION
      SEGA
    OVERWORLD 1
    FROM ADVENTURE ISLAND 2
      HUDSON SOFT

  RESOURCES USED
    GUIDES
      SONIC RETRO
      SSRG
    WALLJUMP AND PEELOUT CODE
      MERCURY
    HOMING ATTACK CODE
      VLADIKCOMPER
    DOUBLE JUMP CODE
      ELECTROBALL
    SONLVL
      MAIN     MEMORY
    NEWNINEKOPALETTEEDITOR
      NINEKO
    MID2SMPS
      VALLEYBELL
    FLEX 2
      SNKENJOI
    SONMAPED
      XENOWHIRL
    FW-KENSC
      MAIN     MEMORY
      CLOWNANNNCY
    SONIC DISASSEMBLIES
      SONIC RETRO

  BETA TESTING
    DEVON

  SONIC TEAM STAFF
    GAME PLAN
      HIROKAZU YASUHARA *CAROL YAS*
    PROGRAM
      YUJI NAKA *YU2*
    CHARACTER DESIGN
      NAOTO OHSHIMA *BIGISLAND*
    DESIGN
      JINA ISHIWATARI TSUKAHARA *JINYA*
      RIEKO KODAMA *PHENIX RIE*
    SOUND PRODUCE
      MASATO NAKAMURA
    SOUND PROGRAM
      HIROSHI KUBOTA *JIMITA*
      YUKIFUMI MAKINO *MACKY*
    SPECIAL THANKS
      FUJIO MINEGISHI
      SHIGERU MIYAMOTO *PAPA*
    ORIGINAL GAME PRESENTED BY SEGA