Creator Backlash: The producer of C2: Judgement Clay was so disappointed with the animation, that he had Tiny (a character from the previous game) put into the game with no changes to his model to show that the previous game's character models were better.
Executive Meddling: The series was hit VERY hard by this during The Fifth Generation of Console Video Games. 63 1/3 was originally going to be titled "Clayfighter III" and appear on a Vapor Ware console called the M2. However, about a year before the M2 was officially cancelled, Interplay abruptly moved development of the game to the Nintendo 64 and retitled it "Clayfighter 63 1/3".
This caused MANY problems during development: character animation needed to be stripped down due to the N64's cartridge limitationsnote This was when Nintendo 64 cartridges were thought capable of only holding up to 96 megs of data, several of the game's planned fighters needed to be cut, etc. Adding insult to injury, the game was rushed to be released during the 1997 Holiday Season, resulting in an Obvious Beta with numerous glitches and underdeveloped ideas. The Clayfighter 63 1/3 debacle was, in fact, so bad that about six months later Interplay released a rental only update to the game titled "Clayfighter: Sculptor's Cut." To make things even MORE messy, a Playstation game titled "Clayfighter X-Treme" was also in development but scrapped for being behind schedule. These problems, combined with 63 1/3's extremely poor critical and public reception, were what ultimately killed the franchise.
Ickybod Clay and a female gorilla called Lucy were planned for C2: Judgement Clay, but were ultimately cut. Ickybod's bio from Clayfighter 63 1/3 even hints at this development, stating that he was "exiled" from that game.
A homeless vigilante called Hobocop was planned for Clayfighter 63 1/3. Nintendo said no due to the alcoholic references.