This level can only be accessed by evil means; either by destroying Central City with the five blockbuster bombs or reliving Shadow's massacre of G.U.N. troops half a century ago in The Doom. Whichever method is used, Black Doom seems satisfied enough at Shadow's pure dark leanings to place him in the vanguard of the attack on the Space Colony ARK. Warping both of them into space, Doom orders Shadow to go ahead of the main army and take out the ARK's defensive matrix, thereby ensuring the Black Arms forces will have a clear path to the Eclipse Cannon.
The exterior of the ARK is choked with mechanical rubble, presumably shaken off the superstructure during the abortive colony drop at the end of Sonic Adventure 2. Making matters even more difficult is G.U.N., who is continuing their orbital defensive strategy; floating military robots and the ARK's own defenses (green energy barriers) also impede the Arms' progress. Shadow can either follow Doom's orders and clear a path, or bypass the defenses and fly into the space station alone.
Regardless as to which route Shadow takes, he must face G.U.N’s defensive mechanism Blue Falcon.
Right when you begin the stage, turn around... the key is right behind you.
Drop down to the Fourth platform with the turrets and the squadrons of GUN Beetles. Just below the level with two turrets is the key.
After the Fourth Checkpoint, you must go through the energy core, and you will see a small platform. Drop down to that platform to get the key. Wait until you are almost to one of the barriers to drop down.
After you pass by the second Defense Unit, you will see another floating platform. Land on it, and get the key at the end of the tunnel.
When you reach the Chaos Emerald at the end, pass it up and get the key at the end of the tunnel.
Missions
Dark
Guide
Mission
Objective
Tips
Destroy the ARK's defenses!
Destroy the four defense units.
The defense units are triangular-winged, slightly cone-shaped, and green. You are able to use a Black Volt or a gun to destroy the defense units.
Tips: Don't disembark from the Black Volt once you are on. Just try to keep its health full. There are two locations in the stage where you can refill its health.
Tips: Get the pistol out of the weapon container and use the spring to reach the upper level. Attack Blue Falcon's missile launchers, then use the dropped launchers when they are destroyed.
Ranking:
Rank
Time (Mins)
≤ 1:50
2:30
3:00
3:30
> 3:30
Behind the Secret Door
Three extra lives.
Trivia
The ARK's level structure bears a great resemblance to Final Chase and Final Rush, the final levels of the Dark and Hero stories respectively of Sonic Adventure 2, the latter of which being Sonic's last stage of the Hero story.
The BGM of this stage can be recognized as a remix of the Final Rush BGM.
The boss for this stage,"Blue Falcon", is the exact name of Captain Falcon's racer in the series F-Zero.
This is one of the three stages that involve the F-6r Big Foot Walkers.
When the player hits the Goal Ring a Chaos Emerald can be seen, however, Shadow does not collect it until after the Blue Falcon is defeated.
When the player hits the Goal Ring, Shadow will go into his "complete mission" stance. But if the player pays attention to Shadow's character, it will sink into the floor. This only works on the Playstation 2 version of the game.
This is the only stage without a hero character or a hero mission.
At the beginning of the level, if you go back a few feet, the Eclipse Cannon can be seen in the background.
Hidden inside the Space Colony ARK is the most powerful weapon, able to pierce stars. The seven Chaos Emeralds are needed to demonstrate its full power or tomorrow's prosperity ritual will all be for nothing. 
