Guilty Gear X2 is generally considered the purest and/or most popular edition of the Guilty Gear (ギルティギア, Giruti Gia) series, beyond any doubt the most important creation of Arc System Works. Even though it brought back the eclectic excessive esthetics of its predecessors, Guilty Gear X2 provided gamers with a more technical approach.
It is considered by many to be the best 2D fighter ever produced, although it has suffered from severe balance issues ever since the first Guilty Gear game, and a lot of 2D fighting fanatics prefer less luxuriant graphics. It uses a gauge system, akin to Street Fighter Alpha's Super Combo techniques, allowing "super" specials and one-hit "Destroy" kills.
GGX2 uses six buttons, generally corresponding to a punch, a kick, a slash [weapon], and heavy slash [slower harder strike]. The fifth button taunts or greets the opponent, who thereby gains tension in his or her gauge. GGX2 also features a Dust button [which can be used to sweep enemies or propell them into the air to initiate air-combos.]
The main characters of the series are Sol Badguy, Ky Kiske, Potemkin, Millia Rage, Zato-1 [Eddie], May, and Potemkin. The main antagonist is Justice, a sentient robot "gear" system who resides at what appears to be the gates of heaven. Throughout the years, however, more characters gained prominence. GGX2's roster contains 23 characters. Although two versions of RoboKy exist.
The game's main slogan "Heaven or Hell, let's rock" fits very well with the overall musical theme of the game. Daisuke Ishiwatari's musical preferences permeate the game's presentation, characters, storyline, and even the names of the special moves yelled by the characters. "Ride the lightning!"
As mention above, several versions and re-editions of Guilty Gear XX exist. Most of which bring minor changes to the original. The main difference, usually, consists of the addition or omission of the RoboKy character, who plays more like a quicker mobile unorthodox variation of the original Ky than the clunky bomb-ejecting robot of later adaptations. The latest version, although not always welcomed by fans of the series, adds Order Sol and A.B.A. to the roster.