Sonic the Hedgehog 20th Anniversary

Sonic the Hedgehog 20th Anniversary (ソニック・ザ・ヘッジホッグ Sonikku za Hejjihoggu 20th Anniversary) is a 2011 platform video game developed by Sonic Team and published by Sega for the PlayStation 3 and Xbox 360. The game primarily allows the player to use Sonic, Shadow and Silver across several stages. Other secondary characters also become playable across the game. The plot follows Sonic's quest to protect Princess Elise after she is kidnapped by his rival Dr. Eggman and is aided by returning allies.

The game has been referred to as Sonic 2011. It was produced in commemoration of the 20th anniversary of the Sonic the Hedgehog series. The game faced no issues during development, which resulted in releasing the product with no existing bugs. Critics praised both versions for short to no loading times, great camera system, no gameplay glitches, simple plot and good character control.

It was basically a remake of Sonic 2006 (official name Sonic the Hedgehog).

Gameplay
Sonic the Hedgehog 20th Anniversary is a platform game with action-adventure elements. The main player characters are the titular Sonic, Silver or Shadow the Hedgehog, but others are available for short periods. Sonic's levels generally focus on speed, with some sections having him run at full speed while dodging obstacles. Other segments see him escorting Princess Elise, who uses a barrier to protect him from certain hazards. Shadow's sections are similarly speedy albeit more combat focused, though some segments see him riding vehicles, such as a motorcycle. In contrast, Silver's levels move at a slower pace, and revolve around his use of telekinesis to defeat enemies and solve puzzles. In certain areas, control is switched to a friend character (Tails or Knuckles for Sonic, Rouge or Omega for Shadow, and Amy or Blaze for Silver), each with their own abilities.

Although every character plays the same levels, each character's unique abilities allow the player to access different areas of each stage and deny the player from accessing certain items. Sonic, Shadow, and Silver start the game with five lives. A life is lost when the characters are struck by an enemy attack without rings or suffer any other type of damage. If the player runs out of lives, the game is over. The goal of the game is to complete three stories and unlock the Last Story. In each story, the player navigates through hub worlds, known as Town Stages, where they can converse with townspeople to progress the story. The main gameplay takes place in Action Stages that become accessible as the game progresses. Some Action Stages require certain abilities to access; for example, one stage requires the Light Speed Dash move to be unlocked. While in Town Stages, players can enter Mission Stages to earn rings, which can be spent on upgrades to their characters.

Several downloadable extensions have been released that add features to single-player gameplay. These include "Very Hard" mode, a more difficult version of the game; "Boss Attack" modes, which allow a playable character to engage in continuous battles with all of the game's bosses; and "Team Attack Amigo" mode, which sends players through a multitude of levels in a set order, changing to a different amigo character every two levels, culminating in a boss fight. The game also features two multiplayer modes: "Tag", where two players must work together to clear levels and collect Chaos Emeralds; and "Battle", a multiplayer mode where two players race against each other.

Plot
The game follows Sonic, Shadow, and Silver in a story intertwined in their respective gameplay modes.

In Soleanna (inspired by Venice), the Festival of the Sun's opening ceremony is disrupted by the arrival of Doctor Eggman who seeks the Flames of Disaster from Princess Elise. He captures Elise before she tosses the blue Chaos Emerald to Sonic the Hedgehog who arrives there. He meets Miles "Tails" Prower and they rescue Elise; Tails distracts Eggman's robots while Sonic and Elise escape. Meanwhile, Shadow saves Rouge the Bat, who drops the Scepter of Darkness that releases Mephiles the Dark, a creature in Shadow's image who reveals Shadow sealed him within the scepter ten years ago, before opening a wormhole which transports Shadow and Rouge to the future: a post-apocalyptic world that is caused by the Flames of Disaster and a fiery monster named Iblis.

There, Silver and his friend Blaze the Cat meet Mephiles, who reveals Sonic as the Iblis Trigger and sends the two back in time using the purple Chaos Emerald. Silver and Blaze are separated upon arrival, with Silver witnessing Eggman's attack on Soleanna and Sonic's departure. He meets Amy Rose, who accompanies him to find but defends Sonic when they find him, while Eggman recaptures Elise. Sonic flees and meets with Tails and Knuckles the Echidna, before Eggman lures them into a trap sending them into the future where Tails discovers Elise and Eggman died one day before Iblis was released. Shadow and Rouge find a shutdown E-123 Omega, and reunite with Sonic, Tails and Knuckles. Using two Chaos Emeralds, they return to the present. Shadow faces Mephiles, and learns that in the future he was imprisoned by Omega, blamed for the destruction. Shadow and Omega then return to the present-day.

Shadow and Silver travel ten years into the past and learn Iblis and Mephiles are parts of the Duke of Soleanna's project to harness the power of the city's god Solaris. The Duke gives Shadow the Scepter of Darkness, which he uses to seal Mephiles, while Silver and the Duke seals Iblis into a young Elise's tears, the dying Duke asks his daughter not to cry for her tears could release Iblis. Sonic fails to reach Eggman's destroyed ship with Elise inside it, but Silver sends Sonic back in time so he can save Elise. While Shadow, Rouge and Omega defeat Mephiles' clones, Silver and Blaze (at the cost of her life) stop Iblis in the future.

After surviving Shadow's attack, Mephiles holds up the purple Chaos Emerald in use and seemingly kills Sonic with an energy blade behind him, causing Elise to cry and unleash Iblis. Mephiles bonds with Iblis, recreating Solaris to rip the time-space continuum apart. As everyone mourns Sonic's apparent death, Elise senses that Sonic may still be alive and Silver realizes that the Chaos Emeralds can revive him. As they are all gathered, Elise gives Sonic a kiss which allows him to transform into his super form who transfers some of his powers to Shadow and Silver, and together they defeat Solaris. Sonic and Elise go back in time, finding Solaris' original form as a single white flame. Elise blows out the candle to erase Solaris from existence and the story's events so that Solaris can befriend Elise again, rebooting the timeline. The game ends with Sonic watching Elise in the festival show; the two display signs of faintly recalling their friendship.