In this game, you control Sonic, Tails, Knuckles, Shadow, Amy, or Espio. 6 people from around the world help each other in a competitive Co-Op game. This game is two games in one, a fanmade version of Sonic 3K and Sonic 2.

Some new features are:
Gameplay - While based on Sonic 3K/Sonic 2 (Based on what Online game you play) they are similar to the official games, but with online improvements.
Chao - Each person has a Chao assistant, each chao can help you with special attacks, uncover shortcuts, and sense Chaos Emeralds.
Chaos Emeralds - There are two ways to get Chaos Emeralds. The first is to find the hidden Chaos Emerald item box, one is hidden in each level, compete to reach it before you opponets! The other is give 200 rings to Omochao after the boss in each level. Once you collect seven Chaos Emeralds, you will unlock your super form, collect 50 rings and press "s" to turn super. Remeber, you lose a ring a second! If you have all of the Chaos Emeralds by Hidden Palace in Sonic 3K, you will unlock your Hyper-Form.
Rings - Like Shadow, you only lose 10 rings when you get hit, collect them quickly! Your friends can collect your rings before you! Rings are not only used to keep you alive, you can also pay other Sonic characters for shortcuts, secrets, and direct trails to the level's Chaos Emearld.
Keys - At the end of each level, there is a sealed boss door. To open the door, you need the 4 keys. Each player must get his/her own key. There is a key only Sonic can get, a key only Tails can get, etc. You can only collect the key by using your characters special abilitys, so you have to collect that key by yourself, seperating from your teammates, but then you must re-group in front of the boss door.
Vehicles- This game features all types of vehicles, from cars to giant mechs. Use them to help or betray your friends.
Teamwork - Sometimes, teamwork is the key. Players must team up to progress, find secrets, and fight together.
...And Betrayel - There are various points you can betray your buddy, whenether it's stepping off that switch in Lava Reef and letting the lava rush over you "friends" when there still in the pit, or grabbing that giant mech and mashing them into pancakes.

Levels in Sonic Genesis: Online:
Sonic 3& Knuckles levels- Angel Island, Burning Paradise, Hydrocity, Marble Garden, Carnival Night, Frozen Cavern, Ice Cap, Launch Base, Flooded Sewers, Mushroom Hill, Fungi Forest, Flying Battery, Sandopolis, Death Pyrimid, Lava Reef, Crystal Caves, Fire Trap, Hidden Palace, Sky Sanctuary, Death Egg Inside, Death Egg Outside, Doomsday, Meteor Herd, Space Station, Docking Bay, Egg Ship, Hyper Space, Dimension X
Sonic 2 levels- Emerald Hill, Chemical Plant, Auquatic Ruin, Casino Evening, Hill Top, Mystic Cave, Oil Ocean, Metropolis, Wing Fortress, Death Egg.

Also, if you don't want to play the normal game, you will be able to enter in a Vs mode to go against your friends, or anyone in the world! The levels will be based on the levels in the game.
Or you could enter the Race mode, where you will choose a character and race against people in different stages from the game, as well as some custom ones.

More on this game soon. We're just releasing this much now.