《SIMPLE Wii 系列 Vol.6 THE 歡樂大決戰》（日文原名：THE ワイワイ・コンバット）是 D3 Publisher 在 2008 年於日本發行的低價遊戲作品之一，隸屬於其長壽的「SIMPLE 系列」之中。這個系列一向以「便宜有趣、快速上手」為號召，作品風格五花八門，主打亂鬥風格的多人對戰動作遊戲，以簡單直覺的體感操作為賣點，試圖將 Wii 的輕鬆遊玩體驗結合街機式的快節奏格鬥。

沒有明確的故事劇情主線，設定在虛構的「格鬥遊樂園」裡，讓各式各樣來自不同背景的角色，從忍者、太空人到搞笑的巨型蔬菜怪物，在不同主題的戰鬥場地中展開對決。這些角色本身沒有太多背景介紹，設計明顯是以誇張造型與搞笑動作為主，重點在於「熱鬧」、「混戰」與「好玩」。主要玩法是 3D 多人混戰形式，每場對戰最多支援四人同場，包括本機雙打與與電腦對手對戰模式。

操作方面，使用Wii遙控器來進行攻擊與防禦。基本操作包括揮動遙控器來做出攻擊動作（如揮拳、揮劍、投擲等），按鈕則用於跳躍、拾取道具或特殊技能。每位角色都有獨特的動作與招式組合，有些偏重速度、有些偏力量，整體操作節奏明快，並加入誇張的打擊特效與搞笑語音，強調輕鬆娛樂的氛圍。

關卡方面則設計成各種趣味主題場景，例如機器人工廠、神秘森林、跳跳床競技場等，部分場地還會加入陷阱或動態地形，讓戰鬥更混亂更不可預測。此外還有大量隨機出現的道具可供使用，例如火箭發射器、巨大錘子或瞬間變身裝置等，這些設計大大提升整體的娛樂性，即使技術上不算精緻，但適合朋友之間胡鬧對戰。

就市場評價而言，屬於非常明確的目標群向作品。由於它定位於低價位市場與簡單對戰遊戲的需求，因此並未得到主流遊戲媒體太多關注或好評。大多數評價指出這款遊戲操作雖然直觀，但略顯單調，場景與角色設計雖有趣但深度不足，容易出現內容重複與耐玩度偏低的問題。即便如此，仍有一群玩家欣賞它作為「派對遊戲」的價值，尤其是小朋友或不常玩遊戲的大人，能夠快速理解規則並立即參與，特別適合家庭娛樂或朋友聚會時短時間的爆笑對戰。

在日本的遊戲店與二手市場，《THE 歡樂大決戰》常被當作入門遊戲或體感遊戲套裝中的補充作品，價格親民且佔用空間小。不算是耐玩或技術性高的格鬥遊戲，但憑著「胡鬧式亂鬥」的概念與簡單操作，仍在Wii多人遊戲陣容中佔有一席之地，也體現SIMPLE 系列一貫「小品也能有樂趣」的理念。對於收藏 SIMPLE 系列的玩家或想要體驗日系體感亂鬥遊戲歷史者而言，依然是值得嘗試的選項。

SIMPLE Wii Series Vol.6: THE Wai Wai Combat (Japanese title: THE ワイワイ・コンバット) is a budget game released by D3 Publisher in Japan in 2008, as part of their long-running SIMPLE Series. Known for its slogan of "cheap and fun, easy to pick up," the SIMPLE Series offers a wide variety of casual games. THE Wai Wai Combat focuses on chaotic multiplayer action battles, promoting simple, intuitive motion controls as its main selling point, aiming to combine Wii’s accessible gameplay with fast-paced, arcade-style fighting.

There is no detailed story mode; the setting is a fictional "combat amusement park" where a colorful cast of characters—from ninjas and astronauts to comically oversized vegetable monsters—battle across different themed arenas. These characters have little to no backstory, clearly designed for exaggerated visuals and humorous animations, emphasizing "fun," "chaotic battles," and "lively excitement." The main gameplay style is 3D multiplayer free-for-alls, supporting up to four players simultaneously, including local split-screen matches against friends or AI opponents.

In terms of controls, players use the Wii Remote to attack and defend. Basic actions include swinging the remote to perform attacks (such as punching, sword-swinging, or throwing), while buttons are used for jumping, picking up items, or activating special moves. Each character features a unique set of movements and attack styles—some focus on speed, others on raw power. The game maintains a brisk action pace, enhanced by exaggerated hit effects and comedic voice clips, creating a lighthearted, party-game atmosphere.

The stages are themed around playful and chaotic settings, such as a robot factory, a mysterious forest, and a trampoline arena. Some arenas also introduce hazards and dynamic elements, adding to the unpredictability of battles. Additionally, a variety of random items—like rocket launchers, giant hammers, and instant transformation devices—appear during matches, significantly boosting the fun factor. Although technically simple and not highly polished, these design choices make it ideal for friends looking for wild and messy battles.

In terms of market reception, THE Wai Wai Combat was very much a niche title with a clear target audience. As a low-priced, quick-play fighting game, it received little attention or praise from mainstream gaming media. Most reviews noted that while the controls were intuitive, the gameplay could feel repetitive, with character and stage designs being amusing but lacking depth, leading to lower replayability. Nevertheless, a portion of players appreciated its value as a "party game," especially for children or casual gamers who could quickly grasp the rules and dive straight into the action, making it a perfect choice for family gatherings or short bursts of hilarious multiplayer mayhem.

In Japanese game stores and secondhand markets, THE Wai Wai Combat is often bundled as an entry-level title or included in Wii motion game collections. Though not a technically deep or highly competitive fighter, its "wild brawling fun" concept and simple controls have secured it a spot within the Wii’s multiplayer lineup. It reflects the SIMPLE Series’ enduring philosophy that "small games can still bring great fun." For collectors of the SIMPLE Series or those interested in exploring the history of quirky Japanese motion-control brawlers, it remains a title worth trying.