Mega Man X7, known as Rockman X7 in Japan, is a video game developed by Capcom. It is the seventh main game in the Mega Man X series and the first to have 3D gameplay. It is the first in the series to appear on the sixth generation of video game consoles and the debut of the series on the PlayStation 2.
It was also released for the PC in Asia, though it suffered from numerous bugs (such as Zero's hair disappearing during gameplay). A patch was later released that fixed numerous bugs.
Mega Man X7 is the first and only game in the Mega Man X series where the main protagonist, X is not available as a playable character from the beginning of the game. Instead, the player must rescue 64 reploids or defeat the eight main bosses in order to unlock him.
X7 is the first and only game in the series to have 3D gameplay in addition to the standard 2D style. It is also the only X series game where X's buster can be fired directionally (although in 2D form like Axl).
Source: Wikipedia, Mega Man X7 , available under the CC-BY-SA License.