| Streets of Rage 3 - Special Edition | Jonathan Hughson | Streets of Rage 3 | Action > Beat 'Em Up | GEN | G | Improvement | 3.13 | 08 May 2002 |
| Dragon Warrior Monsters 2 Ultimate | JonahStrix | Dragon Warrior Monsters 2: Cobi's Journey | Role Playing | GB | L, T, GP, O | Complete | 1.03 | 06 Aug 2018 |
| Warsong Graphics Hack | Jon Najar | Warsong | Strategy > Turn Based | GEN | G | Improvement | 1.0 | 01 May 2008 |
| Contra: Hard Corps Enhancement Hack | Jon Najar | Contra: Hard Corps | Action > Platformer | GEN | T, O | Improvement | Super Cham | 27 May 2012 |
| El Viento Enhancement | Jon Najar | El Viento | Action > Platformer | GEN | G, S, T | Bug Fix | 101010 | 10 Oct 2010 |
| Shinobi III Enhancement Hack | Jon Najar | Shinobi III: Return of the Ninja Master | Action > Platformer | GEN | S, T, GP, O | Improvement | 111009 | 09 Oct 2011 |
| Landstalker Alternate Controls | Jon Najar | Landstalker: The Treasures of King Nole | Role Playing | GEN | GP | Improvement | 1.0 | 12 Sep 2015 |
| The Legend of Zelda NES to FDS Font Patch | JoltJolteon | The Legend of Zelda | Action Adventure | NES | G | Improvement | 1.0 | 17 Jun 2016 |
| FF2us 8×16 Dialogue Font Patch | Joke | Final Fantasy II | Role Playing | SNES | G | Improvement | 1.0 | 11 Mar 1998 |
| Super Mario Bros. Super Special Edition | johnny2301 | Super Mario Bros. | Action > Platformer | NES | G, L, T | Complete | 1.0 | 21 Feb 2020 |
| Zillion Slight Improvement | Johnny | Zillion | Action | SMS | T | Improvement | 1.0 | 30 Dec 2011 |
| Bubble Bobble Hack | John's Program | Bubble Bobble | Action > Platformer | NES | G, S, L, T | Complete | 1.0 | 26 Apr 2002 |
| Master of Monsters Fix | John Osborne | Master of Monsters: Disciples of Gaia | Strategy | PSX | GP | Bug Fix | 5 | 10 Feb 2013 |
| Gex The Gecko in Sonic 1 | JoenickROS | Sonic the Hedgehog | Action > Platformer | GEN | G, S, L, T, GP | Complete | 1.0 | 26 Oct 2020 |
| Uncharted Territory Kaizo | Joe Smo | Super Mario Bros. 3 | Action > Platformer | NES | G, L, T, GP, O | Complete | 1.0.0 | 07 Jul 2018 |
| Road Rash 2 Opponent Edition | joe dailyght | Road Rash II | Racing | GEN | G | Improvement | 1.0 | 10 Nov 2018 |
| Super Mario Bros (EXE) | JMokilovesROMHacking | Super Mario Bros. | Action > Platformer | NES | G, T, O | Complete | 2.0 Final | 18 Jun 2020 |
| Enhanced Donkey Kong Country 2 | JMGO | Donkey Kong Country 2: Diddy's Kong Quest | Action > Platformer | SNES | G | Improvement | 1.0 | 29 May 2019 |
| Super Metroid - Rulers of Ruin | Jkp-troid | Super Metroid | Action Adventure | SNES | G, L, T, GP, O | Complete | 1.0 | 07 Sep 2013 |
| Sonic in Chaotix | JJFTails | Knuckles' Chaotix | Action > Platformer | 32X | G | Improvement | 1.2 | 11 Nov 2006 |
