Sonic 3D Blast Cheats

Final Fight Zone:

To unlock the final battle with Dr. Robotnik, you must collect all seven Chaos Emeralds.
Screen capture:

Press [F9] during game play to save an image of the current screen in the game directory.
Donkey Kong appearance:

Go to some of the trees on the first level to see what appears to be Donkey Kong coming out of a tree.
Secret areas:

There is a secret area in every level, Including the Ice Level and the Volcano level.