Sonic 3 & Sally Acorn2015

Knuckles' Emerald Hunt is a modification of Sonic the Hedgehog 2 that split off from another hack Sonic 2 Adventure Edition. It's main goal is to mimic the Emerald Hunting Gameplay from Sonic Adventure 2/Battle. Playable characters being Knuckles and Tikal, through each stage you must find and collect 3 Emeralds or Emerald pieces. The Game features the radar from SA2, and a secret Sandwich mode in which all the emeralds are replaced with Sub sandwiches and the Master emerald is replaced with a Subway footlong. It also features the Scrapped Hidden Palace Zone and some Sonic 1 Zones

Big's Fishing Derby is a total-conversion modification of Sonic the Hedgehog 2, based on Big's Fishing mini game in Sonic Adventure, the same premise applies. Big must catch froggy to obtain the emerald he swallowed, Dr. Robotnik also is fishing for froggy to obtain all the Chaos emeralds! Big must protect froggy and keep the emeralds out of Robotnik's hands!

Kirby in Sonic the Hedgehog 2 features Kirby and Waddle Dee as the lead protagonists to defeat Dr. Robotnik. Kirby can inhale monitors and most enemies but cannot copy their abilities, Waddle Dee has no unique moves. Life counter function as Health points and the only way to obtain Health is grabbing every 50+ Rings, Lampposts, Randomized 1Up Monitors, or Score every 50000+ points. The hack also contains 4 Difficulty modes. Hidden Palace is restored and fully playable as a 1 Act Zone for Kirby, located somewhere in Mystic Cave Act 2

Portal Gun in Sonic 2 is a Modification of Sonic the Hedgehog 2 that does just that add the portal gun from the portal series into Sonic the Hedgehog 2. Sonic's Sprites have been tweaked, and the Portal Gun is fully functional the portals warping you to their adjacent portal. The portals can also interact with Enemies and Bosses.

Sally Acorn in Sonic the Hedgehog 2 (aka Sally in Sonic 2) is a fan-made ROM of the game Sonic the Hedgehog 2 for the Sega Mega Drive, with Princess Sally Acorn as a playable character in place of Sonic the Hedgehog.

Sally Acorn in Sonic the Hedgehog (aka Sally in Sonic 1) is a fan-made ROM of the game Sonic the Hedgehog for the Sega Mega Drive, with Princess Sally Acorn as a playable character in place of Sonic the Hedgehog.

Based off the unlicensed port of Sonic the Hedgehog for the NES/Famicom by Hummer Team, Somari the Adventurer replaces Sonic with 3 unique new moves. Mushroom Kingdom Zone is a newly added 1-Act level as the first zone.

The citizens of Mobius just can't seem to catch a break. Dr. Robotnik (AKA Eggman) is yet again up to his no good tricks. Factories and pollution are spreading like wildfire as he's once again trying to take over the world. Fortunately, the Sonic Heroes are never at rest, and once again wage their battle to defeat Eggman's evil forces. However, the heroes have landed in double jeopardy. Eggman's madman descendant, Eggman Nega, has escaped from the Ifrit's dimension, and is wreaking his usual havoc in an effort to destroy the world. He's even captured Eggman's top three lieutenants, the ruthless Team Metallix, and reprogrammed them to do his even more evil bidding. Unlike previous instances of Nega's destruction, Eggman is not fazed. He figures that once he's in control of the world, he can take care of Eggman Nega as he pleases. Unfortunately for Eggman, Sonic the Hedgehog isn't having that. Before he can decide who to dispatch where, he receives a call through the communicator Tails gave him. The message: someone's already on the case. Not just someone, but someones! Apparently, Sonic's very own sister, Sonia the Hedgehog has already caught wind of Nega's evil and is out to stop him. Sonic is a bit eased, knowing full well of his sister's strength and agility. She also lets him know that she has found and teamed up with a mysterious young hedgehog who can move things with his mind. Sonic instantly recognizes that Sonia is with his newest ally: Silver the Hedgehog. Silver has once again traveled through time to ensure that the future is free of Nega's tampering (though he really ought to just stay here in the present, you know). Knowing that the two hedgehogs are more than capable of handling the situation, Sonic leaves it to them, and resumes dealing with Eggman. Eggman Nega is well aware that Sonic is busy with his dimwitted ancestor. However, he'd do best not to overlook a certain factor. The S Factor, Sonia and Silver! It's up to you to lead the unlikely tag team of the physically powerful Sonia, and the psychokinetic Silver on their quest to right the wrongs of the evil Eggman Nega!