Rygar is a 1986 platform game developed and published by Tecmo for arcades. The player assumes the role of a "Legendary Warrior" who must navigate numerous levels and defeat enemies with a weapon called the "Diskarmor", a razor-sharp shield with a long chain attached to it that operates like a yo-yo. The warrior intends to defeat Ligar, an evil "dominator". Later ports, particularly the NES and Lynx versions, expanded on the near non-existent story from the original.

The game was subsequently ported to the NES (1987), Commodore 64 (1987), ZX Spectrum (1987), Amstrad CPC (1987), Master System (1988), Atari Lynx (1990), and X68000 (1994); Nintendo released the NES version in arcades in 1987. Emulated re-releases of different versions have also been released for Xbox (2005), Sprint mobile phones (2005), Wii (2009), PlayStation 4 (2014), Nintendo Switch (2018) and Android (2023). A remake, Rygar: The Legendary Adventure, was released for PlayStation 2 in 2002. The Legendary Adventure was remastered for the Wii in 2008 as Rygar: The Battle of Argus.

Rygar received mixed reviews across its various platforms. The most lauded version of the game was the NES version, which was praised for incorporating RPG elements into an otherwise standard platformer, and which has since been recognised as an important early example of the Metroidvania sub-genre. On the other hand, the Commodore, Spectrum, and Amstrad ports were poorly received, particularly their graphics. A common criticism across all platforms was the game's high difficulty. Financially, the games have been successful; the original arcade version proved profitable worldwide, and as of June 2007, the various ports, emulations, and remakes of Rygar have sold 1.5 million units across all platforms.

Rygar is a side-scrolling platformer in which the basic gameplay sees the player character move left to right, with the player able to jump, duck, attack, and climb ropes. Rygar's only weapon is his Diskarmor, a razor-sharp spinning shield that can be thrown some distance whilst staying attached to him, similar to a yo-yo. Available attacks are a standard front-facing attack that can be used when Rygar is either standing up or ducking down, a curved overhead swing, and an airborne attack. It is also possible for Rygar to briefly stun enemies by jumping on them. There is no health in the game, and Rygar is immediately killed upon contact with an enemy (unless jumping on their head) or an enemy's projectile, or by falling from a platform.

There are five categories of items that the player can collect; bonus points, power-ups, extra lives, additional time, and screen bombs (destroys every enemy on the screen). These items can be found in stones that spawn from the earth and are occasionally dropped by defeated enemies. Power-ups boost the player's abilities, but they are not permanent and are lost when Rygar is killed. There are five different types of power-ups; Sun Power (a straight overhead attack to replace the standard circular attack), Crown Power (the ability to kill multiple enemies with one hit), Cross Power (temporary invincibility), Tiger Power (the ability to kill enemies by jumping on them), and Star Power (extension of the Diskarmor's range). Additionally, on rare occasions, a player may find an item with a question mark on it. Every time the player hits the item with the Diskarmor, the item changes into one of the above power-ups.

Each level has a time limit and if the player goes over this limit, a powerful fire monster appears and aggressively tries to kill the player. The longer the player evades him, the faster the monster gets. At the end of each of the 27 levels, there is a safe zone where the player's score is tallied.

The original arcade game also featured what Tecmo referred to as a "Buy-In" feature. When the player has lost all their lives (of which they begin with three), a countdown appears onscreen but if they insert more coins before it reaches zero, they can continue playing from the point of their furthest progression rather than restarting the game from the beginning. However, this option is only available in levels 1-20; during levels 21-27, if the player loses all their lives, they must restart the entire game. The reason for this was to prevent players paying their way to the end of the game by continually dying and resurrecting. Instead, Tecmo wanted to force players to develop the skills necessary to beat the last six levels. The game also utilised a hotseat mechanic whereby two players can play in turn, with each player's progression independent of the other's.

The original arcade version of the game has no real plot beyond the opening text, which reads,