Sonic 2 Chaos Adventure

By Jdpense


This hack aims to be a different take on Sonic the Hedghog 2 with new power ups to be used for each zone.


After releasing Sonic 3 and Knuckles Tag Team, I needed a long break from working on the S3K game since I felt very burnt out from all the programming and endless hours of play testing from my previous hack last year. So I decided to switch to a different game for a year, I will hopefully comeback ready and refreshed for S3K again next year...

Also, this project is a similar concept to an obscure hack I released in late 2017...


Sonic has all of the Chaos Emeralds, but is unable to transform to his super form. He finds a message from a mysterious person who is willing to help him out with his troubles.

New features:

- New menus with a save feature, and with configurations for options (such as controller input)

- "New" power ups added with improvements (Pogo Spring, Rocket Shoes, and Snowboard)

- Levels added to 2P verses mode such as Green Hill, Chemical Plant, and Metropolis

- New dialogue and text boxes added for story and tutorial for power ups

- New Tutorial level added with omochao to interact with by standing close to them and pressing the action ("act") button

- Pause menu added to main game

- "Pitch" mode added to 5 bosses (Emerald Hill's, Chemical Plant's, Aquatic Ruin's, Casino Night's, Hill Top's, Oil Ocean's)

- 2 new bosses in Death Egg Zone

- Some layouts have been changed though mainly for the usage for the power ups

- New palettes for most zones (with the player's palettes adjusting to the mode of the level)

- Lives system changed to be based off of rings

Rule Changes:

- You will lose 10 rings or less each time you die or get hit.

- If you have 1 ring or more while dying, you will respawn to the nearest checkpoint/starting point you last hit touched (even during boss fights).

- Otherwise, if you died with 0 rings, the game is over.

LEVEL SELECT: UP, DOWN, DOWN, DOWN, UP, A + START, at the title screen


- The Pogo Spring is the only power up accessable at the beginning of the game, the other two are currently need to beat more of the game to unlock each of them, but the Level Select cheat code should allow you to unlock the other two power ups early...

- Tails doesn't have access to the Rocket Shoes only Sonic does

- If you want to play a difficult level with challenging puzzles then Metropolis is the right zone for you

- You can't interact with the yellow bumpers in Metropolis, while using a power up... this isn't a bug, but rather it is intentional for sloving a puzzle

P.S. - This hack was only tested on Fusion and Regen, not sure if works any other emulator...

Known bug:

- If the winning player beats the losing player while he or she is near the bottom route of Green Hill in the 2P race can cause the game to crash


- MainMemory for SonLvl

- Clownacy for the Sonic 2 Clone Driver v2

- Xenowhirl for the Sonic 2 2007 disassembly and SonMapED

- Vladikcomper and redhotsonic for the Super Sonic Transform guide

- Nat the Porcupine for the Extended Camera Guide

- Qiuu for PlaneED

- Doc Melonhead and Techokami for the S3K custom item box sprite sheet and the Chaotix sprite sheet rips

- Flare for the Sonic Rush misc items sprite sheet

- Geo Prower for the Sonic Advance 3 Factory sprite sheet

- The Observer for the Metal Sonic sprite sheet rip

- RUSL@2004 for the Infintine "DOOM" version sprite sheet


File Type: rom/mega-drive

File Size: 2.13 MB

Ralakimus @ 2019-12-03 10:43:01

FYI, this doesn't boot up all the way on hardware or Mega Sg. Also, ROM size is supposed to at least be a multiple 2, since the checksum calculation reads things word by word, so an undefined byte can cause potential issues with the checksum check.

Jdpense @ 2019-12-04 07:24:16

Thanks for the info! I will use this tip to fix the checksum when I can! ~

Last modified by Jdpense @ 2019-12-04 07:26:16

Romulok77 @ 2019-12-04 06:57:51

I have tried on more than one android emulator and it does not work.

Jdpense @ 2019-12-04 07:23:07

Yes, I am aware of this issue, I will try to fix the checksum error to have it work on android emulators. I only tested this on Fusion, Regen, and Exdous (PC MegaDrive Emulators) and it worked on those emulators...

Last modified by Jdpense @ 2019-12-04 07:25:03

lordxernom @ 2019-12-04 13:08:25

This hack makes Sonic 2 much better imo. I love power-ups from SMS/GG Sonic games and here layout sections and bosses that takes advantage of them are just amazing. But I found a critical glitch in CNZ. Overall I like this hack.

Video of the glitch mentioned above:

Last modified by lordxernom @ 2019-12-04 13:12:33

Jdpense @ 2019-12-05 19:12:29

Thanks for notifying me! I will fix the glitch when I can! ^^

Super___Sonic_400 @ 2019-12-05 13:09:59

Have you fixed the checksum and replaced the old rom with the new one?

Jdpense @ 2019-12-05 19:11:11

Yes, but the download for the rom with the removed checksum is located on my videos on Youtube. I would post a link to the rom on this site, but I don't think I'm allowed to...

Last modified by Jdpense @ 2019-12-05 19:11:36