Collision Chaos is the second Round of Sonic the Hedgehog CD. Like with every other Round in the game, Collision Chaos consists of two standard Zones that span all time zones, followed by a shorter third Zone set in the future which contains the boss. Geographically, Collision Chaos is located on the Little Planet.
As soon as the first Zone begins, Sonic will find himself at a spin tunnel blocked by spikes, with Amy Rose catching up to him. Shortly afterwards, though, Metal Sonic will burst through the spike blockade and grab the lovestruck hedgehog, then fly off with her. Naturally, it is up to Sonic to give chase. When playing in Time Attack mode (or as Tails in the 2011 remake), this sequence does not happen, and the tunnel will not be blocked.
Collision Chaos is the type of level only a pinball fanatic would love, with neon signs depicting gibberish typefaces flickering all over the place. It has bumpers, fields full of Springs, pinball flippers, and spiked little ball chains that populate the short corridors found at the bottom of the Round. The stage is set in an industrial construction site, similar to that of Spring Yard Zone. The level is not difficult, just that the player should watch out for the random spike traps. That, and getting stuck in the bumper "maze". Zone 2 presents the player with bubble-type bumpers that shatter when bounced off of, along with giant spinning logs with platforms on them.
Much like with Spring Yard Zone Act 2, Zone 2 has two possible exits that the player can reach, each with their own Signpost. Taking the top exit in the 2011 remake will award the player with the "Take the High Road" achievement/trophy.
|A bunch of pinballs floating atop the water. A giant revolving drum rotates overhead. Utilize the Bobbins and flippers to your advantage, something happens to Amy who had been pursuing Sonic…
— Sonic the Hedgehog CD JP manual (translation by Vertekins)
Differences between Time Zones
|This stage in the present is colorful and well-lit. Giant logs in the sky move fast, so watch out!
|Back in the early days, things weren't quite so built up. Most of the floating neon signs are merely large chunks of rock that can be stood on. The spinning logs aren't completed yet, so they merely stand still, making an easy passage around the sky. Flame-spitting towers don't spit flames. Remember to stop the robot transporter, or...
|...once again, the world will be completely changed by Eggman's dictatorship. Most machines are damaged beyond repair, and the lake in the background resembles an acidic waste dump.
|If you manage to destroy all of those machines in the past, the future will change to this utopian paradise. Mechanical plants pump clean oxygen into the air, and a city now bustles in the background.
|Ga — A moth Badnik that sparkles as it flutters.
|Kama-Kama — A mantis Badnik that rolls along the ground, firing its claws.
|Tentou — A bomb-dropping ladybird bot.