《忍者龍劍傳II 暗黑的邪神劍》（Ninja Gaiden II: The Dark Sword of Chaos）是TECMO於1990年在任天堂紅白機（FC/NES）平台推出的動作平台遊戲，為該系列的第二部作品，之後移植到DOS噢Commodore Amiga。作為續作，在保留原作精髓的同時，進一步強化整體的操作性、關卡設計以及劇情演出，並因新增的多項特色機制而備受玩家讚譽。

故事緊接著前作結局的一年後。邪鬼王賈基歐（Jaquio）雖然在隼龍（Ryu Hayabusa）手中敗北，但他的黑暗力量並未完全消失。在賈基歐死後，另外的黑暗勢力黃泉一族開始崛起，首領是名為阿修塔爾（Ashtar）的凶魔天帝，試圖以龍與艾琳（Irene Lew）進行獻祭，打開黑暗之門，用「暗黑邪神劍」復活邪神，再利用其強大力量將黑暗籠罩世界。

當時龍消滅的只是邪鬼王的一部份，他的旅程再次展開，這次的任務是阻止阿修塔爾的陰謀，同時拯救被俘的艾琳。在冒險過程中，不僅要面對黃泉一族的爪牙，還要與邪惡勢力製造出的各種怪物與強大敵人戰鬥，最終進入阿修塔爾的領地~拉夏之塔，展開最後的決戰。

延續前作的核心操作方式，依然可以操控隼龍進行跳躍(A紐)、攻擊(B紐)和使用忍術道具(按上+B紐或者在攀爬時按B紐)。然而，續作引入多項創新的操作系統，極大提升可玩性與策略性。最具代表性的新增機制是「分身影武者系統」。可以收集特殊的道具，召喚最多兩名分身影武者，這些分身會跟隨隼龍的行動，同步攻擊敵人，還可以穿越障礙物並持續攻擊，即使隼龍躲避或跳躍，分身仍能攻擊敵人，大幅提升輸出能力並增加戰術變化。

此外，在牆壁上的移動能力也得到改進。在前作中，需要透過不斷蹬牆跳躍來攀登高牆，而在《忍者龍劍傳II》中，直接沿著牆壁垂直就能攀爬，讓關卡探索變得更加順暢且直觀。忍術系統也得到強化，新增多種強大的忍術道具，包括可進行範圍攻擊的火焰忍術，以及能讓隼龍在短時間內無敵的忍盾術，這些新元素讓戰鬥變得更加多元。

遊戲共分為七大章節，橫跨二十多個小關卡，場景的多樣性與複雜程度遠超前作。關卡設計風格多變，從暴風雪中的山脈到熾熱的火山洞窟，再到黑暗籠罩的阿修塔洛斯堡壘，每個場景都充滿危機與挑戰。值得一提的是，遊戲中加入動態環境效果。例如，第二章的關卡中會出現強烈的暴風雪，會影響移動速度與跳躍距離；第四章則設計火焰強風場景，讓隼龍在跳躍時需要精確計算風向，增加過關的難度與趣味性。

BOSS戰依舊是亮點，每章節的最終關卡都設有強大的頭目。這些BOSS不僅擁有華麗的攻擊方式，且攻擊模式比前作更加多樣，需要靈活運用忍術與分身系統才能擊敗。其中，最終章的決戰分為三個階段，必須先擊敗阿修塔爾後趕到祭壇，隨後挑戰復活的邪鬼王與終極邪神，連續的BOSS戰考驗著玩家的反應與策略。最終龍劍化為靈魂進入艾玲的身體，她就此甦醒。

延續前作的電影式過場動畫演出，並在表現力上更進一步。動畫過場數量增加，人物對話更加細膩，展現更強的劇情張力。每個章節之間的過場動畫進一步刻畫角色的情感與故事背景，讓玩家對隼龍與艾琳的關係，以及阿修塔爾的邪惡計畫有更深入的理解。這種沉浸式的敘事方式，使得《忍者龍劍傳II》不僅僅是一款動作遊戲，更像是互動式忍者電影，這在當時的遊戲市場上極為罕見。

當年在發售後獲得極高的評價，無論是專業評論機構還是玩家都對其給予高度肯定。整體的難度雖然依舊維持在極高水準，而相較於前作更加平衡，但攀牆的Bug相當多，大幅降低挑戰度。關卡設計更加人性化，減少許多不必要的懲罰機制。玩家普遍讚揚遊戲的操作手感、創新的分身系統以及細緻的關卡設計，認為該作是8位元時代動作遊戲的巔峰之一。即便是在今日，仍然被視為FC/NES平台上不可多得的經典動作遊戲。

總結來說，《忍者龍劍傳II 暗黑的邪神劍》以更精緻的關卡、更流暢的操作以及更深入的劇情表現，成功奠定該系列在動作遊戲史上的重要地位，成為許多玩家心目中難以磨滅的經典之作。

Ninja Gaiden II: The Dark Sword of Chaos is an action-platformer developed by Tecmo and released for the Nintendo Famicom/NES in 1990. It is the second entry in the Ninja Gaiden series, later ported to DOS and Commodore Amiga. As a sequel, the game retains the essence of the original while enhancing overall controls, stage design, and cinematic storytelling. Numerous new features were added, earning the game widespread praise from players.

The story picks up one year after the events of the previous game. Although Jaquio, the Demon King, was defeated by Ryu Hayabusa, his dark powers did not completely vanish. After Jaquio’s death, a new dark force known as the Clan of Darkness begins to rise. Their leader, the fiend emperor Ashtar, seeks to sacrifice Ryu and Irene Lew to open the Gates of Darkness. Using the power of the Dark Sword of Chaos, he plans to resurrect the Demon God and engulf the world in shadow.

Ryu’s victory in the previous game only destroyed part of Jaquio’s power. His journey begins anew, this time to thwart Ashtar’s sinister plot and rescue the captured Irene. Along the way, Ryu must battle Ashtar’s minions, monstrous creations, and powerful enemies. His quest ultimately leads him to Ashtar’s domain—Lahja Tower—where the final showdown awaits.

The game retains the core mechanics of its predecessor. Players control Ryu, performing jumps (A button), attacks (B button), and using ninja arts by pressing up + B or B while climbing. However, several new mechanics significantly enhance gameplay depth and strategy. The most notable addition is the Shadow Clone system. By collecting special items, Ryu can summon up to two shadow clones. These clones follow Ryu’s movements and attack in sync, bypassing obstacles and continuously striking enemies even as Ryu dodges or jumps. This mechanic dramatically increases Ryu’s offensive power and introduces new tactical possibilities.

Wall climbing, a key aspect of stage navigation, is also refined. In the original game, Ryu had to repeatedly jump between walls to ascend. In Ninja Gaiden II, Ryu can now climb walls vertically by simply holding the direction, making exploration smoother and more intuitive. The ninja arts system is expanded with powerful new abilities, such as a flame attack that deals area damage and a temporary shield that grants invincibility. These additions make combat more dynamic and diverse.

The game consists of seven acts, spanning over 20 sub-stages. The level design surpasses the original in complexity and variety, with environments ranging from snow-covered mountains and volcanic caves to the shadowy fortress of Ashtar. A notable feature is the introduction of dynamic environmental effects. In Act 2, strong blizzards reduce movement speed and affect jump distances, while Act 4 features fiery winds that alter jump trajectories, adding both difficulty and excitement to the platforming experience.

Boss battles remain a highlight of the game. Each chapter culminates in an intense boss fight, with enemies showcasing elaborate attack patterns and greater variety than in the previous game. Defeating these bosses often requires strategic use of ninja arts and the shadow clone system. The final chapter features a grueling three-phase battle: first against Ashtar, followed by the resurrected Jaquio, and ultimately the Demon God. These consecutive battles push players’ reflexes and tactics to the limit. In the end, the Dragon Sword merges with Irene’s spirit, reviving her.

The game continues the cinematic storytelling style introduced in the original, but with even greater emphasis on dramatic cutscenes. The number of animated sequences is increased, and dialogue between characters is more refined, enhancing narrative tension. Cutscenes between chapters delve deeper into character emotions and relationships, providing greater insight into Ryu and Irene’s bond and Ashtar’s malevolent ambitions. This immersive approach makes Ninja Gaiden II feel more like an interactive ninja movie, a rarity in the gaming landscape of the time.

Upon release, the game received critical acclaim from both professional reviewers and players. While the game maintained a high level of difficulty, it was considered more balanced than the first entry. However, the game was notorious for bugs related to wall climbing, which unintentionally reduced some challenges. Level design became more forgiving, with fewer unnecessary punishment mechanics. Players widely praised the game’s responsive controls, innovative shadow clone system, and detailed stage designs, cementing it as one of the finest action games of the 8-bit era.

Even today, Ninja Gaiden II: The Dark Sword of Chaos is regarded as a classic and a standout title on the NES/Famicom. The game’s refined stages, fluid gameplay, and immersive storytelling helped solidify its place in action game history, leaving an indelible mark on players and securing its legacy as an unforgettable masterpiece.