Kirby in Sonic the Hedgehog 2 is a hack of Sonic the Hedgehog 2 by Lone Devil (Also known as Darkon360) for the Sega Genesis/Megadrive. It features Kirby and Waddle Dee whom replaces Sonic and Tails as the lead protagonists. Kirby can inhale monitors and most enemies but cannot copy their abilities. Lives function as health points and the only way to obtain them is grabbing every 50+ Rings, Checkpoints/Lampposts, Randomized 1Up Monitors, or Score every 50000+ points. The hack also features 4 difficulty modes. Hidden Palace is restored but only as a 1 Act Zone for Kirby, located somewhere in Mystic Cave Act 2.

Sonic the Hedgehog 2 (ソニック・ザ・ヘッジホッグ2 Sonikku za Hejjihoggu Tsū?) is a platform video game developed by Sonic Team and Sega Technical Institute, and published by Sega. The game is an installment in the Sonic the Hedgehog series, and focuses on the protagonist Sonic the Hedgehog and his friend, a fox named Miles "Tails" Prower,[3] who must stop the series antagonist Dr. Ivo Robotnik from stealing the Chaos Emeralds to power his Death Egg space station.Originally released for the Sega Genesis/Mega Drive in 1992, the game was a critical and commercial success, with critics praising it for building upon the original Sonic the Hedgehog game. The game has sold over 6 million copies, making it the second-best-selling game on the console, behind only its predecessor in the Sonic series. Since its initial release, the game has been released in several compilations and download releases for various platforms, which were also generally positively received.

Sonic 2 Long Version (which is released alongside Sonic 2 & Knuckles Long Version) is a more complete version of Sonic 2, which makes it somewhat similar to Sonic 2 Delta. This hack features four levels originally scrapped during Sonic 2's development. No levels have been changed, only added. This hack was written in hex, without the aid of any special hacking programs, because the creator uses a Mac, and no hacking tools had been released on that platform at the time of development.

Sonic the Hedgehog 2: Pink Edition is a character swap hack of Sonic the Hedgehog 2 for the Sega Mega Drive/Genesis, with Amy Rose and Cream the Rabbit replacing Sonic the Hedgehog and Tails respectively. Amy Rose's sprites are designed after her modern look. Amy Rose with classic-style sprites is available to play in the Amy Rose in Sonic the Hedgehog 2 hack. The game was modified by Sonic Retro Member E-122-Psi, with additional programming and coding by other members including MarkeyJester, MainMemory, FraGag, Selbi, and Hayate. Most programming unique from Amy In Sonic 2 such as Cream the Rabbit's gameplay was implemented by Flamewing.