Crystal Egg Zone

Crystal Egg Zone is the seventh and last zone of the Game Gear/Master System Sonic 2. It can be accessed only if you've successfully collected all the Chaos Emeralds in previous zones; otherwise, you get the Bad Ending after defeating Mecha Sonic in Scrambled Egg Zone.

As with all other stages in this game, Crystal Egg Zone consists of two standard Acts followed by a shorter, third Act which contains the Zone's boss.

Crystal Egg is perhaps the least aesthetically offensive of all the final bases Eggman's constructed over the years; a zone of glassy, translucent architecture where even the spikes glow in rainbow hues. Rainbow hues of death. Blocks embossed with the Dr. Eggman pugnacious visage frequently conceal hidden walkways.

Last Boss
The game's last boss battle takes place inside a lightning chamber, which Robotnik makes extra-fatal by throwing gyrating, flower-shaped energy bolts into the mix. However, the boss actually isn't that difficult if you stay inside the transport chutes until the chamber clears; at which point you can leap out, attack Doctor Eggman, and dive back in to safety before his attacks renew themselves.

His final machine destroyed, Eggman beats a hasty retreat down an escape chute. Sonic gives chase, but not quickly enough to stop the fat man escaping via teleporter. Just as the hedgehog thinks all is lost, Tails warps in through the teleport terminal; presumably thrown in there by Robotnik as a means of expediting his retreat. Which has Sonic and Tails running and they suddenly stop and look at the sky, showing an image of the duo. But if the player fails to get all the Emeralds, the same ending will play (with Tails appearing in the teleporter) but it shows only Sonic running and then looking at the sky, showing an image of Tails.

Music
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