From Sonic Retro

<forumuser name="ICEknight" /> ICEknight has tracked down many of the people who worked in the old Sonic games and interviewed them for his website Sonic Database, which also hosts many other prototype related pictures and info.

He's found some hidden things inside the games (like the hidden boss tune in a Sonic 3D prototype, later used in Sonic 4) and likes to make little hacks once in a while, such as implementing the lost warp effect in Sonic 1, Hill Top with IceCap colors, Mecha Flicky in Sonic 2's Death Egg Zone, or Strider Hiryu in Sonic 1.

Relevant Images