Darius II es un juego programado, publicado y distribuido por Taito para recreativa en 1989, siendo posteriormente portado a otros sistemas como Master System, Mega Drive o Game Boy.
Como en todo buen juego de este género, el objetivo de cada nivel no es otro que destruir a los diferentes enemigos que nos vayan apareciendo para al final de cada recorrido enfrentarnos a un jefe de fin de fase con el aspecto de pescado tan típico de la saga, aunque también nos podemos encontrar con algunos subjeres. Como sucede con el original y con la versión de Mega Drive, después de finalizar algunos niveles se nos dejará elegir entre diferentes caminos que nos llevan a fases diferentes, lo que sirve también para alargar la vida del juego.
The game is set in the inner half of the solar system, and has the same branching level structure as Darius. Similar to the first Darius game, Darius II was programmed for multiple screens; while a three-screen version like the original exists, Darius II is more commonly and generally represented as a two-screen game.
The red/green/blue powerups from the first game return, and have the same function: respectively, upgrades to the "missile" main weapon and "bomb" subweapon, and a shield to absorb some damage. Two new power-ups were added: a yellow powerup that adds a new "laser" main weapon that functions somewhat similarly to the bombs, and a rainbow powerup that grants one upgrade to all the players weapons. Actually acquiring these power-ups and the upgrade path is completely different from Darius: a formation of a specific enemy must be completely destroyed (and a given formation may not have a powerup), and every single powerup now grants some kind of upgrade. Further, the various weapons upgrade differently, though the shield upgrade the same as before.
Another new feature in Darius II is the appearance of minibosses known as "captains"; large enemies that appear somewhere in the level before the main boss. In Darius II, these are all smaller versions of bosses from the first game, with similar abilities.
Darius II takes place sometime after the first Darius game. The colonized planet Darius is recuperating from its invasion from the alien Belser Army thanks to that game's heroes Proco and Tiat. Darius' inhabitants have since situated themselves on the planet Olga while Darius' societies, architecture and attacked areas were being repaired. The space flight Headquarters established on Olga picks up an SOS signal coming from Earth, where the first colonists originated before colonizing Darius. The signal included the description of alien ships similar to those of the Belser Army. Suspecting that these might be their remaining Earthling ancestors, the people of Darius sends both Proco Jr. and Tiat Young to help them.
A Mega Drive conversion was released in Japan in 1990; it was later released for the Genesis in the United States and Brazil in 1991, where it was renamed Sagaia. Changes include a boss rush mode (via a code) and various modifications to levels and mechanics, such as the boss Steel Spine being moved to another level and the boss Killer Higia being replaced with a similar creation called Nehonojia. This conversion does not support two players, so the ability to choose between Proco Jr. and Tiat Young was added; Proco plays like normal, while Tiat starts every life off with one power level to every weapon.
A Master System conversion, developed by Natsume, was released in Europe and Brazil in 1992, also titled Sagaia. It is somewhat based on the Mega Drive port, and while Tiat Young and her abilities are still present (though even more limited), many zones (and thus bosses) have been completely removed.