Always composed and produced by SAWANO Hiroyuki (Aldnoah.Zero, Blue Exorcist, Kill la Kill, Zombie-Loan, Guilty Crown), this OST 2 is only included in the "first press" DVD/Blu-ray box, Attack on Titan Vol.4. Unfortunately, it is out of print now and no longer available (second hand only).
So, it contains 11 BGM, which actually are the remaining unreleased tracks of SAWANO Hiroyuki. The style stays basically the same than the previous OST (i.e. electronic, orchestral, classical), but in lower quality, as the first was simply exceptional and varied. The instruments mostly used here are keyboard & piano ; as well as guitars, strings and french horns.
My favorites are: "Shingeki st-hrn-egt20130629 Kyojin" (n°1), a fighting theme seperated in two parts: the first one is electro-orchestral played with keyboard, percussions, strings and french horns; the second (from 2'18") is a cover version of the song "Call your name" (OST1 n°15), the composition is really successful, especially from 3'22" when chorus are entering, accompanied then by percussions and french horns. Very catchy and epic, I recommend it to you!
We have another cover versions of the song "Call your name": "Shingeki gt20130218 Kyojin" (n°3), in acoustic version, only played with guitar and keyboard, quite relaxing; "Shingeki vc-pf20130218 Kyojin" (n°5), still acoustic played with violin and discreet background music (in the first part); and from 3'22", this is a piano version, this quiet and peaceful.
"Shingeki st-hrn-gt20130629 Kyojin" (n°10), is a slower version of "Rittai kidou" (OST1 n°4). I prefer the original than this one. However, from 3'10", I like the part with instrumental version of the song "DOA" (OST1 n°8).
The last track, "Shingeki pf-medley20130629 Kyojin" actually is a medley, fully played with acoustic piano, covering different themes and songs of the anime. It is pretty good but the rythmn is maybe too slow.
In short, this album is dedicated to those who have seen the anime or the collectors. For the others who wish to listen to Shingeki no Kyojin, I highly recommend the OST 1, simply excellent and epic!