Double Dragon (Japanese: 双截龍 (ダブルドラゴン), Hepburn: Daburu Doragon) is a 1987 beat 'em up video game developed by Technōs Japan and distributed in North America and Europe by Taito. The game is a spiritual and technological successor to Technos' earlier beat 'em up, Nekketsu Kōha Kunio-kun (released outside of Japan by Taito as Renegade), but introduced several additions such as two-player cooperative gameplay and the ability to arm oneself with an enemy's weapon after disarming them. Double Dragon is considered to be one of the first successful examples of the genre, resulting in the creation of two arcade sequels and several spinoffs, as well as inspiring other companies in creating their own beat 'em ups.

Originally an arcade game, home versions were released for the NES, Master System, Atari 2600, Atari 7800, Atari ST, Amiga, Amstrad CPC, Commodore 64, Game Boy, Genesis/Mega Drive and Atari Lynx, among other platforms during the series's height of popularity. A remake titled Double Dragon Advance was released for the Game Boy Advance in 2003. The NES version was re-released for the Wii's Virtual Console on April 28, 2008 in North America at a cost of 500 Wii Points. Nintendo also released the Game Boy version on the Nintendo 3DS Virtual Console in 2011.

Wonder Boy (ワンダーボーイ, Wandā Bōi) and the later Monster World (モンスターワールド, Monsutā Wārudo) make up a series of video games published by Sega and developed by Westone Bit Entertainment (formerly Escape).

The series itself consists of the main Wonder Boy series, and the Monster World sub-series. Games may be part of one, the other, or both. This has resulted in a sometimes confusing naming structure resulting in titles like "Wonder Boy V: Monster World III". North America and Europe received every game that was under the Wonder Boy brand, but Japan received one exclusive title that is exclusively part of Monster World.

To further complicate matters, Westone had a unique licensing arrangement with Sega whereby Sega retained the rights to the names "Wonder Boy" and "Monster Land", but Westone retained the rights to everything else. Westone, in turn, had a licensing arrangement with Hudson Soft, who created new characters and titles and ported these games to non-Sega platforms. The most well known of these is Adventure Island, which was more commercially successful than Wonder Boy was.