"Mega Man X2 (ロックマンX2 , Rockman X2) was released in 1994 by Capcom and is the second game in the Mega Man X sub-franchise. It used the same graphics engine from the first installment of the series, but Capcom included an in-cartridge enhancement known as the Cx4 chip to improve semitransparencies and allow for some 3D graphics in the game. Mega Man X3 was the only other game to ever use this chip. Like the first game, it is praised for its soundtrack.
The subtitle Versus X-Hunters is given in the opening story; the Japanese version's full name is Rockman X2: Versus Counter-Hunters.
The game was re-released on January 10, 2006 as part of the Mega Man X Collection for the GameCube and PlayStation 2."
Source: Wikipedia, "Mega_Man_X2," available under the CC-BY-SA License.