For possibly the first time ever, the English version kept the original Japanese intro song, the Japanese voices, and even the original Japanese names of the Mavericks completely intact in the game's localization.
The music in Gate's lab is a high-speed remix of the 3rd X-Hunter stage theme from Mega Man X2
. Also the Sigma battle theme is a remix of both the Sigma virus battle from X2
as well as the first Sigma battle theme from Mega Man X