| Clay Fighter: Sculptor's Cut - Secret characters unlocked | gallaux | Clay Fighter: Sculptor's Cut | Action > Fighting | N64 | GP | Improvement | 1.0 | 07 Dec 2022 |
| ClayFighter 63⅓ - Secret characters and options unlocked | gallaux | ClayFighter 63⅓ | Action > Fighting | N64 | GP | Improvement | 1.0 | 17 Dec 2022 |
| Ultra ClayFighter | Zool | ClayFighter: Tournament Edition | Action > Fighting | SNES | G, S, L, T, GP | Complete | 3.1 | 03 Feb 2023 |
| ClayFighter TE-Tiny's Shorts Fix | DarthMarino | ClayFighter: Tournament Edition | Action > Fighting | SNES | G | Improvement | 1.0 | 31 May 2021 |
| Cliffhanger - no-dim hack | Cluster | Cliffhanger | Action > Beat 'Em Up | NES | O | Improvement | 1.0 | 23 Jun 2021 |
| Clock Tower Deluxe | BobSchneeder45 | Clock Tower | Adventure | SNES | G, L, GP | Improvement | 2.0 | 08 Jan 2023 |
| Clock Tower: Ghost Head ~Yokubari~ | FlamePurge | Clock Tower II: The Struggle Within | Adventure | PSX | S, T | Improvement | 1.00 | 23 Feb 2023 |
| Nazrin Land | DASTARD | Clu Clu Land | Action | NES | G, T | Improvement | 1.0 | 01 Mar 2009 |
| New Clu Clu Land (FDS-hack) | Morgan Johansson | Clu Clu Land: Welcome to New Clu Clu Land | Puzzle | FDS | O | Improvement | 1.1 | 03 Jun 2013 |
| Clue RNG Improvement | link_7777 | Clue | Boardgame | SNES | O | Improvement | 1.0 | 17 Feb 2019 |
| NES Dream Team | biejor1 | Cocoron | Action > Platformer | NES | G | Improvement | 1.0 | 09 Oct 2005 |
| Cocoron screen flash removal | NovaSquirrel | Cocoron | Action > Platformer | NES | O | Improvement | 1.0 | 15 Sep 2020 |
| Final Cocoron | Tedzja | Cocoron | Action > Platformer | NES | G, T | Improvement | 1.0 | 28 Oct 2013 |
| Code Name: Viper - Fully Clothed | Big Hairy Marty | Code Name: Viper | Action > Platformer | NES | G | Improvement | 1.0 | 14 Nov 2017 |
| CodeName: Tenka - New control buttons config | Mr2 | CodeName: Tenka | Action > Shooter | PSX | GP | Improvement | 0.1 | 18 Oct 2016 |
| Colin McRae Rally 2.1 | Lupus Erectus | Colin McRae Rally 2.0 | Racing | PSX | G, GP | Improvement | 1.0 | 24 Nov 2007 |
| Color a Ninja | Slush.Filter | Color a Dinosaur | Other | NES | G | Complete | 1.0 | 07 May 2020 |
| Columns Hi-Score SRAM | BillyTime! Games | Columns | Puzzle | GEN | O | Improvement | 1.0 | 26 Sep 2021 |
| Comix Zone - Calcium kid edition | Vikfield | Comix Zone | Action > Beat 'Em Up | GEN | GP | Improvement | 1.0 | 13 May 2019 |
| Comix Zone SRAM | BillyTime! Games | Comix Zone | Action > Beat 'Em Up | GEN | O | Improvement | 1.1 | 27 Apr 2021 |
