The Black Aliens have hit six major cities around the world. Among them, Westopolis has received the heaviest causalities due to its weakened defence system. Downtown Westopolis has been almost completly destroyed. Unconfirmed sources have also reported seeing a Black Hedgehog in Westopolis.
— GUN Soldier, Shadow the Hedgehog
Westopolis is a human city left in ruins from the attacks of the Black Arms, filled with roads and skyscrapers. Much of the area has collapsed from the explosions of the Black Arms' attack.
After Black Doom appearing before him as the Black Arms invade Westopolis, Shadow the Hedgehog rushes into the city in his search for the Chaos Emeralds. He quickly runs into Sonic the Hedgehog, who asks him to help fight the Black Arms throughout the City, before grabbing the first Chaos Emerald in the midst of the stage. Doom's Eye appears to him not long after, demanding that Shadow instead kill the G.U.N. soldiers defending the city. The neutral path involves going straight to the Chaos Emerald located at the end of the stage.
The following weapons can be found in Westopolis:
- There is a hidden area to the right, just before the Jump Panel that leads to the second checkpoint. The player must jump over the pit to reach the platform on the other end with the key.
- A pulley can be found shortly after the second checkpoint, which must be used to reach the second key.
- Just before the third checkpoint, two Gun Beetles can be seen hovering by a platform. The player must quickly Homing Attack the enemies before they are destroyed to reach the platform with the third key.
- There is a gate directly to the left of the third checkpoint. The player must Slide or Spin Dash under it and break the container in the back to get the 4th key.
- After the Goal Ring are a set of Jump Panels that lead to another skydiving section; the final key can be seen on the right side.
|Annihilate the GUN forces!||Defeat all 35 GUN enemies in Westopolis.||10 GUN enemies should have been defeated by the time you reach checkpoint #2, 20 by checkpoint #3, 26 by checkpoint #4, 33 before checkpoint #5, and all 35 before the final checkpoint.
|≥ 30,000 points|
|< 5000 points|
Leads to: Digital Circuit
|Find the Chaos Emerald!||To complete the Normal Mission, all that is required of the player is that to reach the Goal Ring with the Chaos Emerald in it. Missions like these did not require the player to finish of any of the Black Arms or GUN Soldiers, but sometimes defeating them will make it easier for the player to get through the Stage faster.|
|≥ 32,000 points|
|> 10,000 points|
Leads to: Glyphic Canyon
|Drive off the black creatures!||Defeat all 45 Black Arms in Westopolis.||23 Black Arms should have been defeated by the time you reach checkpoint #2, 29 by checkpoint #3, 33 by checkpoint #4, 42 before checkpoint #5, and all 45 before the final checkpoint.
|≥ 30,000 points|
|< 5000 points|
Leads to: Lethal Highway
In other media
Westopolis is mentioned in the Sonic the Hedgehog comic book series and its spin-offs published by Archie Comics. In this media, it is a Human/Overlander settlement in Eurish and a city-state of the United Federation. In the post-Super Genesis Wave continuity, Westopolis is a city found in Northamer.
- To 100% complete the game, the player will have to play this stage a total of 326 times.
- In Expert Mode, Dr. Eggman wishes Shadow good luck via a hint marker.
- If the player hits the hint bubble explaining how to switch guns with Sonic as a partner, he will comment on the guns afterwards saying "Personally, I wouldn't be caught dead using those things."
- At the start of level during the skydiving section, Shadow will say "Hmm.. 'The promised time' huh? Well then, time to go fulfill this promise." There is no mention of a "promised time" before this. Instead Black Doom said "Bring the Chaos Emeralds to me "as promised."
- Black Doom does mention the promised time during the Semi-Dark route, but this happens after Westopolis, not before.
- This is the first game in the series to feature Sky Diving done at the beginning of the stage and at the very end (past the Goal Ring in normal mode and before it in Expert Mode).
- The Stage has 36 GUN Soldiers instead of just 35.
- If one were to play with Sonic with a second controller, not only does he Homing Attack Black Arms, but he can also hurt GUN Soldiers with it. He seems to function more like Shadow than other hero characters; he can activate switches, put out fires, open locked key doors, and he even has a scripted Sky Diving sequence which can be done at the end of the level.
- Strangely, if the player is running at full speed with Sonic and then pulls the control stick down to skid to a halt he shares the same hovershoe sound effects as Shadow when he brakes.
- The hint bubble where Sonic suggests to Shadow that they use the homing attack on GUN beetles to cross a gap was originally supposed to have Sonic use the word "piss" (i.e., "Hate to piss off GUN..."), but it was changed to "tick" in the final version.
- If a laser fires during the Doom's Eye intro scene, the crates underneath said laser will remain intact.
- It is possible to avoid collecting the first Chaos Emerald using a well-timed Spin Dash. Skipping this Emerald will have no effect on overall gameplay however.
- If the player meets Doom's Eye, touches the second checkpoint, dies, then teleports to the first Checkpoint (with Doom's Eye as his active partner), Doom's Eye will actually comment twice about the Chaos Emerald; once for getting close enough, and the other line upon its acquisition.
- The stage's music was remixed for the Enemy Territory stage in the Sonic Forces DLC, Episode Shadow.
- Shadow the Hedgehog Prima official guide