Gigalopolis Zone is the second zone of Sonic Chaos for the Sega Game Gear (where it is known as Gigapolis Zone in the West), and Master System. In keeping with the other stages of this game, Gigalopolis consists of two standard Acts followed by a shorter, third Act which contains the Zone's boss.
This level sees Sonic run through an urban environment at night, under the stars. Some of the level resembles a construction site, with orange, metal frameworks and seemingly incomplete block walls. The background displays various high-rise buildings as well. This zone also introduces the 3/4 loops in the Game Gear series, which were first shown in Sonic the Hedgehog's Star Light Zone.
Gigalopolis is one of the only zones in Sonic Chaos to have two different music tracks for the Game Gear and Master System ports respectively.
||Smash through walls with the Super Spin Dash. Watch where you jump, or Dr. Robotnik's traps will make you a chump! Metal-o-Turtles and bugs are out to get you. Fight the Bead Worm Boss to clear the zone.
— Game Gear version manual
||Lights glitter on the night skyline as you spring from level to level. Race through corridors, then jump on top and grab those Rings!
— Master System version manual