Sonic 3D: Flickies' Island/Hidden content

PC Version

Missing render

KojiChao found what appears to be a piece of concept art piece for the final boss, possibly used as part of an 'explosion' sequence after defeating the boss. The background is very dark and can barely be seen, unlike the Sonic Crackers-esque backdrop seen in the final game. The boss is also equipped with items from its third and fifth phase.

Unused Special Stage intros

These images may have been meant to be used for loading screens shown before the special stage. However, since the Special Stages don't require much loading time (they appear instantly), the images went unused. Perhaps this means the Saturn special stages were originally going to be used in the PC version?

Mega Drive Version

Invincibility track

The invincibility track is actually longer than 18 seconds long. Only part of the track plays normally. The full track can be found here.