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.
ShadowChaos Controls himself into an area based-around the Eclipse Cannon of the ARK, expressing frustration with the confusion of his memories. This however, puts him 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, along with his relationship with Maria. Shadow dodges a bullet from the Commander's gun, while the Commander himself questions if Shadow really did lose his memories. Shadow on the other hand promises to submit to justice if it turns out he really was responsible for the death of the ARK's population, walking away and leaving the Commander to question his own beliefs.
Shortly after starting the level, Shadow then notices the ARK's passageways collapsing all around him. After traversing through the debris, he eventually encounters Doom's Eye, who 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.
The following weapons can be found in Cosmic Fall:
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.
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.