

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!
Froggy has lept into a warp ring and managed to collect all the chaos emeralds! Dr. Robotnik's aquatic roboticizer due to their energy is activated. Robotnik getting the readings realizes the emeralds are near by and decides to take a fishing trip to gather them. Big fishes to get his pet frog back, but upon seeing Robotnik knows he's up to something, and figures froggy has something he wants so Big decides to keep whatever it is out of Robotnik's hands.

Platform / Action / Science fiction
Metal Sonic Hyperdrive is a modification of Sonic the Hedgehog that stars Metal Sonic as the main character role - more specifically a reprogrammed Metal Sonic. The hack also features other characters besides Metal such as: Sonic,Lone Devil (KAZ),Kirby, and even Somari! Each coming with their own unique abilities: Metal can use the Super Peel-Out, and Maximum Hyperdrive Attacks, Sonic can Spindash in traditional fashion. Somari can spindash, but in a less traditional fasion, Lone Devil can use his Sythe to attack and freefall, and Kirby can inhale enemies, no copy abilities.

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

Sonic the Hedgehog Megamix (commonly shortened to Sonic Megamix) is a work-in-progress multiperson disassembly modification of the original Sonic the Hedgehog videogame for the Sega Mega Drive / Genesis, developed by Team Megamix and more recently moved to the Sega Mega-CD. The game features the ability to play as one of five different characters: Sonic the Hedgehog, Mighty the Armadillo, Shadow the Hedgehog, Miles "Tails" Prower, and Knuckles the Echidna. It is an extensive reworking of the original game, featuring new art, music, abilities, layouts, and other things.

Sonic 2 XL is a hack of Sonic the Hedgehog 2 for the Sega Mega Drive by Captain Bozo and Ranger. Rings are replaced with onion rings, and Sonic becomes fatter after eating them.

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.

Tails and Charmy are the flying types with the ability to soar through the air nothing stands in their way, and with Each carrying a legion of friends when super or hyper, Dr. Robotnik's forces don't stand a chance! Knuckles and Vector are the power types delivering devistating blows to Robotnik's Badnick army combine that with the ability to Glide, climb walls, and Power Dash, these two are the roughest, toughest dudes around. As if the Teams weren't enough to sway you new powerups make their rounds aswell: Home in on Robotnik's forces with the Homing Sheild, Burn those bots with a fire sheild. Short-circuit them with an electric sheild, If a watery grave awaits you a bubble sheild is just around the corner. The Sol Emeralds have also managed to cross dimensions through the Special Zone but not to worry Team Sonic and Chaotix are on the job! Using both the Power of the Chaos and Sol Emeralds will unlock a very familiar power.... can you collect all 14?