"Mega Man X3 (ロックマンX3, Rockman X3) is a video game released in 1995 by Capcom. It was the third game in the Mega Man X sub-franchise and the last to appear on the Super Nintendo.
Like its predecessor, Mega Man X2, Capcom included the Cx4 chip to allow for some limited 3D graphics (more specifially, vector graphics) and transparency effects. Mega Man X3 was the first game in which Zero is a playable character in addition to X."
Source: Wikipedia, "Mega_Man_X3," available under the CC-BY-SA License.