| Contravania: Dawn of Sorrow | I LOVE PHEROMOSA | Castlevania: Dawn of Sorrow | Role Playing > Action RPG | NDS | G, L, GP | Complete | 1.0 | 29 Aug 2022 |
| Control a NOOB | Master ZED | Mortal Kombat 3 | Action > Fighting | SNES | GP | Improvement | 1.0 | 23 Jul 2005 |
| Control Freak | Kejardon | Super Metroid | Action Adventure | SNES | GP | Improvement | 1.2 | 18 Aug 2009 |
| Controller input display | jazzthief81 | Tetris | Puzzle | NES | G, O | Improvement | 1.1 | 16 Jan 2021 |
| Cony | ConyTheBun | Super Mario Bros. | Action > Platformer | NES | G, L, T, GP | Complete | 1.0 | 16 Nov 2022 |
| Cooey Found Weed | Cooey | Mother | Role Playing | NES | G, T | Complete | 1.0 | 28 Jan 1999 |
| Cookie's Original Sprites | SCD | Panic Restaurant | Action > Platformer | NES | G | Improvement | Final | 21 Sep 2020 |
| Cooking Princess | elDexter | Paper Mario | Role Playing > Action RPG | N64 | L, GP | Complete | 1.0 | 04 Jul 2022 |
| Cooly Skunk (PAL Region Fix) | Ice Man | Cooly Skunk | Action > Platformer | SNES | O | Improvement | 1.0 | 11 Oct 2020 |
| Cooly Skunk Enable Password Hack | denim | Cooly Skunk | Action > Platformer | SNES | O | Improvement | 1.1 | 27 Mar 2022 |
| Cornelius in LttP | pollux | The Legend of Zelda: A Link to the Past | Action Adventure | SNES | G, T | Improvement | 1.0 | 15 May 2016 |
| Cornfed The Monkey: Santa's Last Hope | Moxy | Mega Man 5 | Action > Platformer | NES | G, T | Complete | 1.0 | 11 Feb 2000 |
| Correct boss names for Street Fighter II' - SEC | SCD | Street Fighter II': Special Champion Edition | Action > Fighting | GEN | T, GP | Improvement | Final | 12 Jun 2017 |
| Cosmic Balloon Assault | Quick Curly | Balloon Fight | Action | NES | G, L, GP, O | Complete | 1.0 | 05 Aug 2015 |
| COTM Auto Dashing | Dev Anj | Castlevania: Circle of the Moon | Role Playing > Action RPG | GBA | GP | Improvement | 1.0 | 27 Sep 2021 |
| Crack Down Arcade colors | fabio | Crack Down | Action > Shooter | GEN | G | Improvement | 1.0 | 02 May 2020 |
| Crazy Daydream | redfeatherz | Super Mario Bros. 2 | Action > Platformer | NES | G, L, T, GP | Complete | 1.05 | 07 Feb 2021 |
| Crazy Otto - NES Edition | CosmicToons | Ms. Pac-Man (Tengen) | Action | NES | G | Complete | 1.0 | 24 Mar 2021 |
| Crazy the Hedgehog | Chaoxilla | Sonic the Hedgehog | Action > Platformer | GEN | G, S, L, T, GP, O | Complete | 1.0 | 30 Jul 2014 |
| Critical Hit Rate Fix | Rabite | Final Fantasy I & II: Dawn of Souls | Role Playing | GBA | GP | Bug Fix | 1.0 | 27 Jan 2021 |
