| Joust More | Grimlick | Balloon Fight | Action | NES | G | Improvement | 1.0 | 01 Jan 1998 |
| Joust (Arcade Hack) | Immutable | Joust | Action | NES | G, T, O | Improvement | 1.0 | 03 Oct 2015 |
| Journey To The West - A Super Mario Bros Hack | Inkbox Software | Super Mario Bros. | Action > Platformer | NES | G, L, T | Complete | 1.1 | 21 Feb 2022 |
| Journey to Silius: Fair Edition | Adrian Schiller | Journey to Silius | Action > Platformer | NES | GP | Improvement | 1.0 | 11 Jan 2023 |
| Journey to Silius – Boss Run | Quest Games | Journey to Silius | Action > Platformer | NES | L, GP | Improvement | 1.3 | 25 Dec 2018 |
| Journey to Silius Plus | alzen | Journey to Silius | Action > Platformer | NES | G, L, T, GP | Complete | 1 | 09 Dec 2011 |
| Journey to Silius MMC5 Patch | Dracula X | Journey to Silius | Action > Platformer | NES | O | Improvement | 1.2.0 | 28 Oct 2021 |
| Journey to Silius Level 5 Music Replacement | NK358 | Journey to Silius | Action > Platformer | NES | S | Improvement | 1.01 | 08 Feb 2020 |
| Journey to Silius - Original Sprites | RichterSnipes | Journey to Silius | Action > Platformer | NES | G | Improvement | 1.0 | 22 Sep 2015 |
| Journey to Silius - Fixed Samples | TakuikaNinja | Journey to Silius | Action > Platformer | NES | S | Bug Fix | 1.0 | 29 May 2022 |
| Joshua: the Restored Levels | Immutable | Joshua & the Battle of Jericho | Puzzle | NES | G, L, T, GP | Complete | 7.0 | 19 Aug 2018 |
| Joshua (Redesign) | Immutable | Joshua & the Battle of Jericho | Puzzle | NES | G, T | Improvement | 7.1 | 23 Mar 2018 |
| JonBound - Dark Future | Blue Antoid | EarthBound | Role Playing | SNES | G, L, T, GP, O | Complete | 2.0 | 01 Jan 2001 |
| Joji Fuku O Kite (Little Girls Wearing Clothes) | Flake | Tiles of Fate | Puzzle | NES | G, S, T, O | Complete | 1.0 | 27 Mar 2013 |
| Johnny Jackpot | Laputan Machine | Chrono Trigger | Role Playing | SNES | T, GP | Improvement | 1.0 | 21 Jul 2016 |
| Joe & Mac Improvement | the jabu | Joe & Mac | Action > Platformer | NES | G, GP | Improvement | 1.0 | 08 Nov 2015 |
| Joe & Mac - Fastrom | kandowontu | Joe & Mac | Action > Platformer | SNES | GP | Improvement | 1.0 | 15 Feb 2023 |
| Joe & Mac - Enhanced Colors | Pyron | Joe & Mac | Action > Platformer | GEN | G | Improvement | 3.0 | 28 Dec 2014 |
| JobexiMod - SMB | Jobexi | Super Mario Bros. | Action > Platformer | NES | L, GP | Improvement | 1.0 | 11 Jan 2022 |
| Jimbo's Big Adventure | Megafield64 | Super Mario Bros. | Action > Platformer | NES | G, L, T, GP | Complete | 2.0 | 06 Nov 2014 |
