Cosmic Fall

Cosmic Fall is one of the six final stages in Shadow the Hedgehog. It takes place in the Ark, which is apparently collapsing, due to the powers of the Black Arms. This level is known for its immediate difficulty. There is no main floor or ground unlike most other levels, Second to that, many platforms are simply floating as they fall, alarms are blaring everywhere, and to top it off, there are only fifteen minutes to finish the stage.
 * Not to be confused with Cosmic Wall.

Cosmic Fall is one of five sixth stages and can be reached by completing the Hero mission of Iron Jungle, the Normal mission of Space Gadget, or the Normal mission of Lost Impact.

How to approach
The player must either gun down Dr. Eggman's blimp in the Iron Jungle, flee towards Prof. Gerald's lab in the Lost Impact, or obtain the Chaos Emerald in Space Gadget to arrive at Cosmic Fall.

Story
In the level's opening cutscene, Shadow Chaos Controls himself straight into a confrontation with the Commander, who reveals the reason for his antipathy against him as he witnessed the Ultimate Lifeform's creation by Gerald and Black Doom fifty years ago. Shadow dodges a bullet from the Commander's gun, but promises to submit to justice if it turns out he really was responsible for the death of the ARK's population.

Shortly after starting the level, Doom's Eye asks Shadow to retrieve a Chaos Emerald located in the ARK's power plant. As they enter the first interior area, Vector the Crocodile makes a surprise entrance, desperately searching for the ARK's computer room. The objective Shadow chooses ultimately depends on what actions the player takes in the final room of the power plant. Fall from the doorway to the floor and you'll be forced to complete the dark mission. However, you can also Triangle Jump across breakable panels or Light Dash to an elevated platform on the other side, from which you can traverse one more section of crumbling debris before finding the computer room and completing Cosmic Fall's heroic mission.

Go the extra distance to complete the hero mission, and Black Doom manifests himself, a scuffle ensues, and Vector fights on your side for what it's worth. Settle for the dark mission and Dr. Eggman pops up with his Egg Dealer, determined to stop Shadow from tarnishing his grandfather's legacy.

Key locations

 * 1) While riding the transport into the Ark the first time, hold to the left to get the key as you are whizzing by.
 * 2) After the third Checkpoint, stand on the corner of the platform after a piece falls and the key will run right into you.
 * 3) Jump across the rotating platforms after the Fourth Checkpoint and stay on the top portion until you reach the final one with the key.
 * 4) After the Sixth Checkpoint use the Jump Vehicle to reach the top platform area using pulleys. When you reach the top, turn around and the key is in space over a spinning platform.
 * 5) Using a series of Dash Panels, you will fall a long way down. Don't bother using the speed circles, but instead, fall down and get the key that is on top of the right pillar before the rocket.

Dark
Ranking:

Leads to: Egg Dealer

Normal
There is no Normal mission for Cosmic Fall.

Hero
Ranking:

Leads to: Black Doom

Behind the Secret Door
A switch. Once activated the switch open a nearby door with an extra life and it also creates ring trails that are used to light dash through the rest of the stage. Very helpful when completing the Hero Mission and during Expert Mode due to the fact that it becomes hard to fall of near the end with the light speed dash.

Trivia

 * This stage led to one of Vector the Crocodile's most famous (or perhaps infamous) lines, "Find the computer room!".
 * The name of this stage, 'Cosmic Fall', is a reference to the Sonic Adventure 2 level ''Cosmic Wall'. However, instead of Eggman climbing the outer rim of the ARK, Shadow is trying to survive as the colony falls apart.
 * The music for this stage is also used as one of the music tracks for the Egg Hangar in Sonic and Sega All-Stars Racing.
 * This is the only stage where Shadow spares Eggman after defeating him (provided the player fulfills the dark mission).