West Side Island

West Side Island is presumably the island which is pictured on the Sonic 2 title screen.

Hill Top Zone, one of West Side Island's varied areas.

Not to be confused with Sonic the Hedgehog - Westside Island, a hack of Sonic 1.

West Side Island, also known as The Illusionary Island, is the setting for Sonic the Hedgehog 2 on the Mega Drive, as told by the Japanese manual. Miles Prower lived there before his first meeting with Sonic, receiving the nickname "Tails" from the resident animals. The island's peaceful idyll is shattered when, before the start of the game, Doctor Robotnik comes to West Side searching for the Chaos Emeralds.

Sonic the Hedgehog 2

The Mega Drive Sonic the Hedgehog 2 is the only game to have unequivocally visited West Side Island; Sonic the Hedgehog 2 (8-bit) (along with many other early Sonic games) instead took place on South Island. Areas visited by Sonic and Tails on West Side Island include:

• Emerald Hill Zone, grassy plains with waterfalls and Mobius strips. Typical Tropical Island cliché.
• Chemical Plant Zone, an industrial factory filled with pink, toxic Mega Mack.
• Aquatic Ruin Zone, semi-submerged ruins in an overgrown forest.
• Casino Night Zone, a huge, glitzy casino city with slot machines and pinball.
• Hill Top Zone, an earthquake-prone area with blue rocks and lava caves.
• Mystic Cave Zone, vine-festooned caverns beneath the island's surface.
• Oil Ocean Zone, a massive petrochemicals refinery polluting the sea with black sludge.
• Metropolis Zone, Robotnik's great city-factory, with oversized pistons and cogwheels.

And above the island:

• Sky Chase Zone, where flying badniks patrol the island's airspace.
• Wing Fortress Zone, the Doctor's aerial fortress.

And even higher above:

• Death Egg Zone, the fat man's own personal doomsday moonlet.

Sonic Drift 2

Several locations in Sonic Drift 2 are the same as those in Sonic 2 (namely Emerald Hill, Casino Night, Hill Top, and Mystic Cave), so obviously occur on West Side Island too. Many of the other racetracks are Zones with no pre-existing appearences, so it is possible that several of these (like Desert Road or Dark Valley) are also located on West Side.

Sonic Mania

In Sonic Mania, there are two zones present that were already present in Sonic 2, Chemical Plant Zone and Oil Ocean Zone, but this game presents two more zones that are evidenced to be on West Side Island by transitions linked to the aforementioned zones. They are:

• Studiopolis Zone, an urban area home to Dr. Eggman's TV studio, which is close to Chemical Plant Zone.
• Mirage Saloon Zone, a desert with a Wild West motif, which is located near Oil Ocean Zone.