Sonic The Hedgeblog on X: In early prototype versions of Knuckles

Sonic The Hedgeblog on X: An early trailer for 'Sonic Shuffle' shows early versions of the intro CG sequence. In this spot, Knuckles' chest and the stage image are different. /

Sonic & Knuckles (prototype; 1994-05-25)/Hidden content - Sonic Retro

Knuckles' Chaotix prototypes -The 32X Database

Sonic 3 and Knuckles - Prototype ProtoKnuxFinal10x by Abbysek on DeviantArt

Sonic the Hedgehog 3 (prototype; 1993-11-03)/Comparisons - Sonic Retro

Sonic The Hedgeblog

Sonic The Hedgeblog on X: A comparison of Knuckles' model from Original to DX in 'Sonic Adventure'. His head changed quite a bit across the versions. / X

10x Sonic the Hedgehog 3 - Prototype Knuckles with by Abbysek on DeviantArt

Prototype Knuckles With Cutscene Palette by SonicInDeviantArtLol on DeviantArt