Volcano Valley Zone
From Sonic Retro
Volcano Valley Zone, the fifth zone in Sonic 3D: Flickies' Island, ramps up the difficulty with a layout based entirely inside a lavalike environment. A misplaced fall usually spells death for Sonic, which contributed to the major challenge factor in this level. The boss of this level also took place in a lava environment, where you have to jump on his lava pipes and hit him, while still avoiding the fire he spews out.