SONIC ONLINE
Sonic the Hedgehog 2 ONLINE

Sonic 2 with friends. Run the zones together, race to the goal ring, battle in the PvP arena and meet everyone in the lobby.

Free fan project · Windows 10 / 11 · needs your own copy of Sonic 2 (2013)

Play Sonic 2 online

Every zone of Sonic the Hedgehog 2, playable with up to 8 players, with a shared lobby, levels, rings to spend and leaderboards.

Players together in the Death Egg, the last zone of the adventure
New · Adventure

The whole game, as a team

Play Sonic 2 from Emerald Hill to the Death Egg in one run with your friends, zone after zone like the original game. Three lives each: lose them all and you watch your teammates, then come back when they clear the zone. Beat the final boss together, and a gold star appears next to your name for good.

Players of every character chatting in the online lobby, next to the leaderboard
Lobby

Meet other players

A big Emerald Hill lobby with an island for every zone, leaderboards, chat and parties of friends.

Sonic, Amy, Fang, Cream, Tikal and Rouge as a team in Chemical Plant Zone
Co-op & race

Every zone, together

Clear the zones as a team (enemies, rings and bosses are shared) or race your friends to the end. Time attack for record chasers.

Vector, Espio, Amy, Ray, Mighty and Knuckles fighting in Emerald Hill
PvP

The arena

Up to 8 players. Spin into your rivals to make them drop their rings: the last one standing wins. Find opponents, or play a friendly match with your party.

The character shop with the new characters
New · Characters

Rings, levels & 9 new characters

Bank your rings, level up and unlock characters in the shop: Tails and Knuckles, and now Mighty, Ray, Amy, Espio, Fang, Tikal, Vector, Cream and Rouge, with their own powers (Mighty's hammer drop, Amy's hammer, Fang's popgun, Tikal's mid-air punch, flight for Ray, Cream and Rouge) and colour variants for everyone.

Sonic, Amy, Cream, Tikal and Rouge running together in a special stage
New · Emeralds

Special stages, together

Found the stars of a checkpoint? Invite the players of your act and run the half-pipe together, with the team's rings counted together. Each Chaos Emerald gives a permanent bonus on the rings and experience you earn.

Emerald Hill Zone in fullscreen, with a wider view
Display

See more of the level

A wider view than the original, in a window, a borderless window or fullscreen.

11 zones to clear

From Emerald Hill to the Death Egg: finish a zone to unlock the next one.

Emerald Hill Zone
1Emerald Hill
Chemical Plant Zone
2Chemical Plant
Aquatic Ruin Zone
3Aquatic Ruin
Casino Night Zone
4Casino Night
Hill Top Zone
5Hill Top
Mystic Cave Zone
6Mystic Cave
Oil Ocean Zone
7Oil Ocean
Metropolis Zone
8Metropolis
Sky Chase Zone
9Sky Chase
Wing Fortress Zone
10Wing Fortress
Death Egg Zone
11Death Egg

How to play

Three steps, about two minutes.

Download

Get the package above and unzip it anywhere (not in "Program Files").

Add your game

Start SonicOnline.exe. The first time, select the Data.rsdk file of your own copy of Sonic the Hedgehog 2 (2013 / Retro Engine).

Sign in

Press Enter on the title screen: create an account (a confirmation e-mail is sent) or use Google. See you in the lobby!

Questions, teammates, bug reports, new versions: join the community on Discord.

Credits

Sonic Online stands on the shoulders of these people.

Sonic the Hedgehog 2 (2013)

Christian "Taxman" Whitehead and Simon "Stealth" Thomley, published by SEGA. Retro Engine (RSDK) by Christian Whitehead.

RSDKv4 decompilation

Rubberduckycooly and st×tic — RSDKModding/RSDKv4-Decompilation. Not our code: used under its license (non-commercial, credited), included in the package.

Extra characters (shop)

Mighty and Ray: sprites from Sonic Mania (SEGA, Christian Whitehead, Headcannon, PagodaWest Games, Hyperkinetic Studios), sheets from The Spriters Resource. Fan-made sprites (The Spriters Resource, Custom / Edited): Amy Rose by E-122-Psi; Tikal by SunnyVies; Fang and Vector by Akimaco; Cream & Cheese by FroggyMudd; Rouge by Zig Sonar; Espio by Geo the Fox, Deebs, Tanuke, Radth, Silverbolt, Skylights and others. Thanks to all of them.

Sonic Online

Online mode, lobby, arena and servers. Libraries: SDL2, libogg, libvorbis, GLEW. Sign-in: Keycloak.