When you begin the stage, take the route that leads you to the GUN Beetles. Before jumping onto the second air saucer, destroy the alien substance to the left behind the GUN Beetle to find the key.
Get on the air saucer after the second Checkpoint, and navigate to the rear of the area where the key is hidden.
Look to your left after going through the big blue door following the large grinding section.
The key is on the path just before you drop down to the bottom level following the seventh Checkpoint.
Use the air saucer to navigate the black ooze near the Chaos Emerald, and you will find the final key.
So far, the Black Arms have been winning the war against the humans and the heroes. However, G.U.N. has given Earth hope by launching a counterattack on the Black Comet and Black Doom is scrambling for reinforcements, so much so that he has called Shadow the Hedgehog to provide backup and some of his army to fight off G.U.N. forces.
Upon meeting Knuckles, Shadow learns he is determined to defeat the Black Arms once and for all. Even if Shadow and Knuckles work together, they will fight not Black Doom, but rather Eggman's Egg Dealer.
The following weapons can be found in Black Comet:
The player must defeat fifty GUN Soldiers to finish the Dark mission on this stage. Throughout the stage, the player will be riding an air saucer often. There are few places that the player need to divert from the main path in order to find GUN Soldiers. After the first Checkpoint, ride the Air Saucer to the right of the tunnel farther down, and get onto the land on the right. This will lead to two GUN troopers. When the player reach the next air saucer, The player should have defeated six GUN Soldiers.
After the fifth checkpoint, the player will get on Air Saucer and ride through a canal. There is a lot of flying Big Foots in the canal, but on the upper paths, there are more GUN beetles as well. When the player reach the end, avoid going into the warp hole, so that the player can gets the Troopers that He missed.
After the sixth Checkpoint, the player will come up to a red vine. If the player were going for the hero path, a shortcut would be present here. Since the player is not, make sure to get to every portion of this area and defeat all the GUN Soldiers.
In the large area with the Gold worms, defeat the Black Assassin Soldiers in order to lower the barrier. When the player reach the next area that the player can walks on, Light Dash across to the door and touch the seventh Checkpoint.
The player must reach the center of the comet. Begin by using the air Saucer after the first Checkpoint, and go underneath the bridge that is straight ahead. If the player keep continuing straight, the player will eventually reach the second Checkpoint.
From the second checkpoint, get on the air saucer, and go straight ahead until the player reach two GUN Troopers. From there, go to the right to get Knuckles, and use the speed ramp to boost yourself to another platform. Activate the switch when the player gets there, and ride the platform up to the next level.
After going through the blue door, the player will drops down to a lower area. Run down the path, and at the end, get on the Air Saucer. Ride it to the other shore, and run down the hallway. After using the saucer to get to the land on the right, destroy the Black Assassin, and jump across the platforms to the other side. Enter the warp hole.
The next part after the fourth Checkpoint is a straight path. When the player see a wide open area, the player will need to be on an Air Saucer. Use the Dash Ring to get into the sea of black, and go to the left to get on the land. At the end of a long path with many GUN Beetles, the player will enter a warp hole.
After the Sixth checkpoint, you will enter a large circular area. Grind down the first red vine, and walk along the path until the player reach the second torch. From there, drop straight down, and the player will land where the player need to be.
When the player reach the next Air Saucer, go straight in the large area and defeat the three Black Steel Soldiers to lower the barrier. When the player reach the land again, Light Dash using the Rings, and go through the door to the seventh checkpoint. the player should be able to get to the end pretty easily from here.