Yasuhiro Takagi was not involved in this album. The "Y.T. / DOLPHIN" credit in the booklets of both this album and G.S.M. Sega 4 doesn't mean "by Y.T.
and DOLPHIN," but rather "by Y.T.
a.k.a. DOLPHIN." Yosuke Okunari explicitly clarifies this in the liner notes of
this recent compilation album: he says the composer of Gain Ground, Golden Axe, and Genesis E-SWAT is "DolphinことY・T."
Y.T. = You Takada = DOLPHIN
As far as I can tell, Yasuhiro Takagi was never credited as Y.T. for any of his early works in games or albums, and it's just a coincidence that he was credited as "yt" on the Virtua Fighter 4 Evolution soundtrack.