Simulated Twilight Town

The Simulated Twilight Town is a world that appears in Kingdom Hearts II, and makes a brief appearance in Kingdom Hearts 358/2 Days. It is a false Twilight Town created by Ansem the Wise as an attempt to keep Roxas contained, while also throwing off Organization XIII. It was created using the same technology Ansem used in Radiant Garden's Space Paranoids, and can be entered by similar means. It is a nigh-perfect recreation of the real Twilight Town, as it has some glitches in the form of the Seven Wonders of Twilight Town. Ansem even recreated every resident of the town, using data samples of each person's heart in the real town. Although keeping to their usual attitudes, they do mostly act under Ansem's influence, though he is unable to completely control them.

Kingdom Hearts 358/2 Days
After Sora, Donald, and Goofy's journey through Castle Oblivion, Ansem the Wise, operating under the alias "DiZ," convinces Naminé to move the trio to his lab in Twilight Town to protect them from Organization XIII, as the castle was still under their control. However, in order to restore Sora's memories completely, Ansem sends Riku to capture Sora's Nobody, Roxas. Once Riku returns with an unconscious Roxas in tow, Ansem placed Roxas inside the Simulated Twilight Town in order to hide Roxas from the Organization until it was time for Roxas to return to Sora.

Roxas' story
To prevent Roxas from escaping, DiZ altered Roxas' memory with data to make him believe that he was a normal teenage boy who lived in Twilight Town with his best friends Hayner, Pence, and Olette. In spite of that, Roxas begins experiencing strange dreams of Sora's exploits during his first adventure. In the digital Twilight Town, summer vacation is coming to a close, and Roxas and his friends try to have some last-minute fun before returning to school. Unfortunately, his fun is constantly being interrupted by strange white creatures and two men in black coats. One of the cloaked men, Axel, was sent into the digital Twilight Town and attempted to persuade Roxas to return to the Organization. When Roxas showed no signs of remembering either his friendship with Axel or his time with the Organization, Axel resorts to violence to bring him back. As time goes on, Roxas begins to regain his memories of the Organization, with the help of the Keyblade and Naminé, who acts as a guiding figure to Roxas.

Everything Roxas knew began to crumble around him, and he could only trust Naminé. On his last day in Twilight Town, Ansem freezes time inside the simulated realm and summons Roxas to the Old Mansion outside of town. Roxas enters the mansion and witnesses Ansem and the other cloaked man capturing Naminé. Roxas then obtained her drawings, identical to one on the library table, and draws Sora's crown necklace in one of the three circles on the table. After completing the symbol, Roxas gains access to Ansem's computer room. There, he finally regains his full memory, remembering that he was once a member of Organization XIII, who had used him for his ability to wield the Keyblade, and that he had left it to find his past, only to be captured by Riku.

In his rage, Roxas destroys the digital version of DiZ's computer, then fights with Axel one last time in the simulated mansion's basement, before merging with Sora. Sora then awakens from his year-long sleep in the real Twilight Town.

Sora's story
The virtual Twilight Town was first visited by Sora late into his fight against the Organization. He enters the virtual Twilight Town with the help of Hayner, Pence, Olette, and King Mickey. Sora enters a portal left by Axel in the virtual basement of the mansion to access The World That Never Was.

Kingdom Hearts III
After his failed Mark of Mastery exam, Sora returns to Twilight Town with the intention of trying to find a way to help Roxas become his own person. With the help of Hayner, Pence, and Olette, who wish to become friends with Roxas like their counterparts in the virtual Twilight Town were, Sora examines the computer in the old mansion. Pence is able to link the computer to the Hollow Bastion OS in Radiant Garden with the help of Ienzo. However, Ansem, Seeker of Darkness and Xemnas confront Sora outside the old mansion about how his plan is futile. While Sora wants to put Roxas's heart inside the virtual Twilight Town so that he can live there, Ansem reminds him that the town is just data.

Using the data of Roxas that Ansem the Wise had encoded into the virtual Twilight Town, Ienzo is able to alter a blank replica and prepare it to house Roxas's heart so that Roxas can have his own body separate from Sora. After the real Organization XIII is defeated, Ienzo, Even, and Ansem the Wise do this again with Naminé's data from the virtual Twilight Town, giving Naminé a replica body as well.

Differences from the real Twilight Town
There are many notable differences between the virtual and real versions of Twilight Town, which include:
 * Yen Sid's Tower only exists in the real Twilight Town. The train to it in the simulated Twilight Town leads nowhere, and is considered a ghost train.
 * The field and battle themes in the simulated Twilight Town are completely different from those of the real Twilight Town. Likewise, as the Twilight Town that appears in Kingdom Hearts Chain of Memories is not the real one either, it uses the same pieces as that of the simulated Twilight Town (however, the music pieces stay the same as those of the real Twilight Town when Sora visits the fake one). However, whenever Roxas visits Twilight Town in Kingdom Hearts 358/2 Days, the music is the same as the simulated Twilight Town.
 * Hayner, Pence, and Olette have little knowledge of Roxas's existence in the real Twilight Town (though they feel that they have met Sora, Roxas's original self, even before meeting him), but they are his best friends in the simulated Twilight Town. In Kingdom Hearts 358/2 Days, Roxas and Axel briefly met Pence; later Roxas met Hayner and Olette as well, although they never reached the extent of friendship shown in the simulated Twilight Town.
 * Setzer is the Struggle champion in the simulated Twilight Town. In the real Twilight Town, it is Seifer, though this could be because Seifer beat Setzer in the last competition, taking his place as champion.
 * In the simulated Twilight Town, there is a standalone building with a candy shop. In the real Twilight Town, there is a Moogle Shop instead.
 * Only the item shop is functional in the simulated Twilight Town, but all shops are in the real Twilight Town.
 * Evidently Sora must go to the simulated Twilight Town only once—and he discovers that the computer in the simulated world's Old Mansion's basement is destroyed (by Roxas), while it is in perfect shape in the real Twilight Town.
 * The save points in the basements of the Old Mansion are different—the basement in the simulated Twilight Town uses Type B while the one in the real Twilight Town uses Type A.

Trivia

 * During Sora's story, only the Computer Room (since this is where the user is taken) and Basement Hall are playable in the virtual Twilight Town. If Sora tries to leave this part of the mansion, he will say that leaving the computer room doesn't feel right, and that something is causing the door to the Basement Corridor to not open.
 * The simulated Twilight Town has different music from the real Twilight Town, but strangely, in the Final Mix, when viewing the cutscenes from the simulated Twilight Town in Theater Mode, some of them contain the music from the real Twilight Town. Also, when Sora enters the simulated Twilight Town near the end of the game, the music stays the same as the real Twilight Town (in both versions of the game).