Klayton (in the form Muckster The Cat and Globmeister) appears along with the bird enemy at the beginning of a match and races across the screen with the number of the round on a balloon tied to him. The fish enemies make a cameo in the character select screen. The samurai enemy is featured in the 2-player select screen in the Tournament Edition.
Baleog and Erik appear in the Clay Keep as the faces carved on the wall.
ClayFighter 63 1/3Edit
Earthworm Jim is a playable character in this game.
Like Earthworm Jim, Boogerman from the interplay game of the same name appears in the game as a playable character.
The theme of the stage Clayribbean Cruise is a remixed tune from Claymates.