1992年SEGA推出的《音速小子2》在16位元遊戲史上佔有極為重要的地位。作品由Sega Technical Institute（STI）與部分初代《音速小子》的Sonic Team成員共同打造，並於Mega Drive（Genesis）平台推出。因為初代的成功引起全球注目，當年在開發時就備受期待。SEGA甚至創造全球同步發售活動「Sonic 2sday」，可見當時的自信與氣勢。

故事發生在神祕的西方島（West Side Island）。相傳這座島曾經擁有高度繁榮的古代文明，他們依靠七顆具有神秘力量的混沌翡翠（Chaos Emeralds）建立起富饒世界，但因濫用力量而遭天譴，文明毀滅，寶石也因此被封印在島內深處。某日，索尼克在旅途中來到這座翠綠寧靜的島嶼，而他的出現也吸引一隻天生與眾不同的小狐狸──擁有兩條尾巴的「泰爾斯」（Miles “Tails” Prower）。從小因外貌遭嘲笑的他，被索尼克的速度與勇氣深深吸引，於是默默跟在索尼克身後。

然而西方島的安寧並未持續太久。索尼克的宿敵蛋頭博士（Dr. Eggman / Robotnik）也追蹤而至，企圖奪取被封印的混沌翡翠，以啟動他最新打造、足以統治世界的太空站兵器「死亡蛋（Death Egg）」。為了阻止這場災難，索尼克與泰爾斯展開旅程，穿越森林、遺跡、化工廠、空中戰艦，甚至最終登上宇宙基地。經歷一次又一次的交鋒後，索尼克最終獨自踏入死亡蛋，擊敗機械索尼克與蛋頭博士的巨大機甲，使太空站爆炸墜落。若玩家未取得全部七顆混沌翡翠，會看到由泰爾斯駕駛 Tornado 迎接索尼克的普通結局；若集齊寶石，則能欣賞索尼克以超級索尼克（Super Sonic）形態突破險境的真結局。

在玩法方面，延續初代的高速橫向卷軸設計，並且在動作節奏與關卡架構上更加成熟。玩家可以單人操作索尼克，也可以與 AI 或第二位玩家一同操控泰爾斯冒險。索尼克在本作中首次獲得具有重大意義的招式「回轉衝刺」（Spin Dash），能在原地蓄力後瞬間加速，讓遊戲流暢度相較初代大幅提升，避免角色因地形停頓而需要重新助跑的尷尬。

關卡內容相當多樣，共包含十一個Zone，每個Zone擁有一到兩個關卡，並在最後迎戰蛋頭博士的載具。首先會從草原與海岸的Emerald Hill出發，進入錯綜複雜的Chemical Plant，再潛入水下遺跡Aquatic Ruin，甚至造訪彈簧與霓虹遍布的 Casino Night。後期還會在飛機機翼上奔跑於Sky Chase，最終踏入毫無戒指可撿、令人緊張的終章Death Egg。

本作也以特殊關卡著稱。當玩家在一般關卡中收集滿50枚金戒後，只要穿越星型碑便能進入著名的半管道3D特殊關卡。這裡索尼克與泰爾斯需要在向前捲動的空間中收集充足戒指以通過檢查點。若成功集齊七顆混沌翡翠，索尼克便能變身超級索尼克，獲得極高的速度與近乎無敵的狀態，但會持續消耗戒指，使玩家在關卡中必須更講究節奏。此外，遊戲還提供兩人分割畫面的對戰模式，可在數個關卡中比拼速度、戒指、分數等項目，或在特殊關卡中競賽誰能取得更多戒指。

當年上市後獲得壓倒性成功，無論玩家或評論都對其高速爽快的節奏、更多元的關卡設計、色彩鮮明的畫面、動畫以及令人難忘的音樂給予高度肯定，其中 Chemical Plant Zone 的配樂至今仍被視為系列名曲。新角色泰爾斯也深受喜愛，使系列角色陣容更具魅力。憑藉豐富的內容與流暢設計，它在Mega Drive平台上售出超過六百萬套，是該平台第二暢銷作品，僅次於初代《音速小子》。時至今日，《音速小子2》依然被視為系列最具代表性的作品之一，也是90年代橫向動作遊戲無可取代的經典，其影響力持續延伸到後續的《音速小子3 & 納克魯斯》，並成為現代重製與合輯版本中不可或缺的篇章。

Released by SEGA in 1992, Sonic the Hedgehog 2 holds an exceptionally important place in the history of 16-bit video games. The title was developed by the Sega Technical Institute (STI) together with several Sonic Team members who had worked on the original game, and it launched on the Mega Drive (Genesis) platform. Because the first Sonic the Hedgehog had achieved worldwide success, the sequel was highly anticipated even during development. SEGA was so confident that it created the global simultaneous launch event “Sonic 2sday,” a clear display of its ambition at the time.

The story takes place on the mysterious West Side Island. According to legend, this island was once home to an advanced ancient civilization that built a prosperous society using the power of seven mystical gems known as the Chaos Emeralds. However, their misuse of that power brought divine punishment, leading to the destruction of their civilization and the sealing of the emeralds deep within the island. One day, during his travels, Sonic arrives on this verdant and peaceful island. His appearance attracts the attention of a young fox born with two tails—Miles “Tails” Prower. Mocked since childhood for his unusual traits, Tails finds inspiration in Sonic’s speed and courage and begins to follow him quietly.

The tranquility of West Side Island does not last. Sonic’s long-time nemesis, Dr. Eggman (Robotnik), soon arrives as well, seeking to seize the sealed Chaos Emeralds in order to power his latest weapon of global domination—the Death Egg, a massive space station. To prevent this looming disaster, Sonic and Tails begin their adventure, journeying through forests, ruins, chemical factories, aerial battleships, and ultimately into outer space itself. After many confrontations, Sonic enters the Death Egg alone, defeating both the robotic Sonic doppelgänger and Eggman’s massive final mech, causing the station to explode and fall. If the player has not collected all seven Chaos Emeralds, the ending shows Tails piloting the Tornado to retrieve Sonic; if the emeralds are gathered, Sonic is seen escaping as Super Sonic in the true ending.

In terms of gameplay, Sonic the Hedgehog 2 builds upon the high-speed side-scrolling design of the first game while refining the pacing and stage structure. Players can control Sonic alone or embark on the adventure with Tails, either controlled by the AI or by a second player. Sonic also gains an iconic new ability in this installment: the Spin Dash. This technique allows him to charge power on the spot and burst forward instantly, greatly increasing the game’s flow compared to the original and preventing the awkward pauses caused by losing momentum on slopes.

The game features a wide variety of stages, totaling eleven Zones, each containing one or two Acts and ending with a battle against one of Eggman’s machines. Players begin in the grassy coastal Emerald Hill Zone, move into the intricate pipeline maze of Chemical Plant, dive into the submerged ruins of Aquatic Ruin, and visit the neon-lit, spring-filled Casino Night. Later stages include running on the wings of an airplane in Sky Chase and finally venturing into the tense, ring-less final challenge of the Death Egg.

The game is also notable for its Special Stages. When players collect 50 rings in a regular stage and pass a Star Post, they can enter the famous half-pipe 3D Special Stage, where Sonic and Tails must gather enough rings while running forward through a twisting tunnel. If all seven Chaos Emeralds are obtained, Sonic can transform into Super Sonic, gaining incredible speed and near invincibility at the cost of continuously draining rings, adding a new layer of strategy to stage traversal. Additionally, the game includes a split-screen competitive mode where two players race through select stages or compete in Special Stages to see who can collect more rings.

Upon release, Sonic the Hedgehog 2 achieved tremendous success. Both players and critics praised its exhilarating speed, more varied level design, vibrant graphics, expressive animation, and unforgettable music—especially the Chemical Plant Zone theme, which remains iconic. The introduction of Tails further enriched the series’ cast and was widely embraced by fans. With its abundant content and refined mechanics, the game sold over six million copies on the Mega Drive, making it the platform’s second best-selling title, surpassed only by the original Sonic the Hedgehog. Even today, Sonic the Hedgehog 2 is regarded as one of the franchise’s defining masterpieces and a timeless classic of 1990s side-scrolling action. Its influence continued into Sonic 3 & Knuckles and ensured its place in modern remasters and collections, where it remains an essential entry.