This album, released in August 2012, on the occasion of the 25th anniversary of Metal Gear, actually is a compilation of the most memorable themes from "Metal Gear Solid 4: Guns of the Patriots" (n°1, 2, 3, 4, 5), "Peace Walker" (n°7, 8, 9) and "Online" (n°6).
So, there is nothing new for those who already have these OST.
Note the track n°2 is supposed to be a new version orchestrated by TODA Nobuko and sung in Hebrew by Jackie PRESTIE, but there are only some minor changes ; tracks n°3 and 7 are performed by The City of Prague Philharmonic Orchestra ; and tracks n°5, 6 & 9 are medleys very long (combining various themes).
My favorite tracks are: "Overture ~ Metal Gear Saga" (n°1), simply epic, composed by the famous Harry GREGSON-WILLIAMS (The Martian, Shrek 1-2-3, The Chronicles of Narnia Chapter 1 & 2, Kingdom of Heaven, Gone Baby Gone) ; '"Metal Gear Solid 4: Guns of the Patriots Medley" (n°3), other awesome symphonic music, and of course "Heavens divide", beautifully sung by Donna BURKE who, amongst others, has collaborated with the famous anime composer KANNO Yôko, on the song "After All" (from Turn A Gundam Original Movie Soundtrack). Really moving musically, every time I listen to this song it makes me want to shed some tears.