《熱血硬派 番外亂鬥篇》（熱血硬派くにおくん 番外乱闘編/Nekketsu Kōha Kunio-kun: Bangai Rantō Hen/Double Dragon II / Hot-Blooded Tough Guy Kunio: The Further Brawls）是由Technōs Japan於1990年12月7日製作並發行的遊戲，是熱血系列首款登陸Game Boy平台的作品，同時也是紅白機熱血硬派(FC)國夫君系列的續作。遊戲可以有兩人同時遊玩，並擁有1M的記憶體。海外版由Acclaim發行，名稱為Double Dragon II，角色更換成雙截龍的人物。重製版於2012年8月8日在3DS Virtual Console推出。

故事設定在宗方興業社長的獨生子，宗方裕二，愛上了熱血高校的"麥當娜"美穂子。在將她擄走並打傷前來阻止的朋友弘，國夫與阿力得知消息後，決定再次聯手出發，從學校前往宗方興業大樓。

沿途他們需要與來自宗方興業的太保們進行戰鬥。主要的戰鬥方式是使用揮拳（按A）和踢擊（按B）來擊敗敵人。還有其他的招式：1.飛踢：先踢暈對方，然後再按B。2.先對敵人揮拳三下，讓對方暈眩後再按A就可以用直拳擊倒。3.同時按下、A和B就能蹲伏，可以暫時避開攻擊。當呈現跪姿時按下任何按鍵就能使出上升上勾拳。4.靠近昏迷的敵人，按A就能攻擊敵人三次，按B能將敵人推倒後扔在地上。此招數對頭目無效。5.當敵人即將倒下時，按下任何按鍵就能跳在對方身上後踐踏。

遊戲提供簡單、正常和困難三種難度設定，如果設定為簡單模式，玩家最多只能通過第一關。正常和困難模式的結局相同。

角色的生命值歸零時將會死亡，生命值用心形符號表示，一開始有兩顆心，生命值為三個，總共有六個生命槽。有兩次續關的機會。畫面左下方會顯示主角的狀態。需要注意敵人手中的武器，一旦被擊中，將會造成嚴重傷害。即使擊敗敵人，也無法拿到他們手上的武器並使用。

遊戲共有十個階段。一開始將在熱血高校附近的街道和商店街進行戰鬥。隨後，將移動到火車站，進入新區域後將自動恢復生命值。第一個頭目是業餘拳擊冠軍Tatsuya，出現在高中附近的火車站。第二個頭目是使用鉛管武器的暴走族村田，出現在購物區的火車站附近。第三個頭目是健美運動選手Futoshi，出現在第二個火車站的盡頭。第四個頭目是高中生相撲選手Tameuemon，出現在宗方興業大樓門前。最後的頭目是出現在宗方興業頂樓辦公室的宗方裕二。

"Hot-Blooded Tough Guy Kunio: The Further Brawls" (Nekketsu Kōha Kunio-kun: Bangai Rantō Hen/Double Dragon II) is a game developed and published by Technōs Japan on December 7, 1990. It is the first game in the Hot-Blooded series to be released on the Game Boy platform and serves as a sequel to the Famicon (FC) game, Hot-Blooded Tough Guy. The game supports two-player gameplay and has a memory of 1 megabyte. The overseas version, titled Double Dragon II, was published by Acclaim. The characters in this version were replaced with those from Double Dragon. A remake of the game was released on August 8, 2012, on the 3DS Virtual Console.

The story revolves around Kunio, the only son of the president of the Souhaku Corporation, who falls in love with Miho, aka "Madonna," a student at Nekketsu High School. After kidnapping Miho and injuring his friend Hiroshi who tries to stop him, Kunio and Riki, upon learning the news, decide to team up again and head from the school to the Souhaku Corporation building.

Along the way, they must battle the Souhaku thugs. The main fighting techniques involve punching (press A) and kicking (press B) to defeat enemies. Other moves include: 1. Flying kick: Kick the opponent first and then press B. 2. Punch the enemy three times to stun them, then press A to knock them down with a straight punch. 3. Press A and B simultaneously to crouch, temporarily avoiding attacks. While crouched, pressing any button will perform an uppercut. 4. Approach a dizzy enemy and press A to attack them three times, or press B to knock them down and throw them on the ground. This move is ineffective against bosses. 5. When an enemy is about to fall, press any button to stomp on them after jumping on top of them.

The game offers three difficulty settings: Easy, Normal, and Hard. If set to Easy mode, players can only progress through the first level. The endings for Normal and Hard modes are the same.

When a character's health reaches zero, they die. Health is represented by heart symbols, starting with two hearts and three lives, totaling six health bars. Players have two chances to continue. The character's status is displayed in the bottom left corner of the screen.

Players must be wary of weapons held by enemies, as being hit by them causes serious damage. Even if enemies are defeated, players cannot pick up and use their weapons.

The game consists of ten stages. Initially, battles take place in the streets and shopping district near Nekketsu High School. Subsequently, players will move to the train station, where their health will automatically be restored upon entering new areas. The first boss is Tatsuya, the amateur boxing champion, appearing near the high school's train station. The second boss is Murata, a delinquent armed with a lead pipe, appearing near the shopping district's train station. The third boss is Futoshi, a bodybuilder, appearing at the end of the second train station. The fourth boss is Tameuemon, a high school sumo wrestler, appearing in front of the Souhaku Corporation building. The final boss is Kunio's rival, Yūji, appearing in the office at the top floor of the Souhaku Corporation building.