Submitted by: Saxman

In Sonic 3, Knuckles had yellow coloured socks, but by the time he went into Sonic & Knuckles he had green socks. This image proves that Knuckles was always meant to have green socks, but due to some difficulties with the palette he was unable to. As you can see, Both the lives icon and HUD have turned green since they use the same palette. In the final version, the HUD doesn't even pop up until Knuckles flees the scene.

Submitted by: SonicCD [aka Jan]

Here is Sonic standing outside the first Special Stage Entrance. Again, he has his Sonic 2 sprites. The dark green in this image also appears darker in the final game, but that might just be the scan.

Click the image for a larger version.

Submitted by: Wiseman

Yet another early prototype image. The only real difference here is the main Sonic & Tails sprites used, as they are from Sonic 2.

Submitted by: Dr. Zachary

Again, Sonic 2 sprites were used as placeholders in early versions of Sonic 3.