NOT A REQUEST THREAD. This thread is only for comparing if you've already heard them, not to ask for the songs. You can compare things that are really being heard, or which version you like more.
Before you ask:
OST - Original/ Official Sound Track (the one used in the albums)
GST - Game Sound Track (the one used in-game)
A lot of songs, of course, have better OST versions than GST versions, ending up in epicness or 'meh, OK.' There are some songs that have better GST versions than their OST versions.
Anyway, time for some of my impressions:
IIDX:
-TROOPERS's ending guitar is softer in the OST. I could barely hear it.
-Do it!! Do it!!, no more, no less, is the same fucking song, despite bits of beat changes.
-Anisakis has a drum roll that souns similar to CaptivAte ~SABAKI~ in about 1:55 of the song. It's more epic than the GST version.
-oratio's back-up vocals are louder in the OST.
-MEI's pause from the 190~200 BPM part is shorter in the OST.
-AGEHA has more bass drums in the latter part of the song. The GST version totally sucked.
-GENOCIDE's OST intro is different from the GST's.
-Daisuke is a bit longer in the OST, but it's still made of win.
-lower world is longer in the OST, and it almost reached 3:00.
GFDM:
-¥ShinchoushinTION¥'s DrumMania GST is a lot better than the OST version. The rapid bass pedals should've been used in the chorus of the OST version IMO.
-TAMAYURA's and Die Zauberflöte's (whatever difficulty) DrumMania GST is also better than the OST version. I love the loud drums.
-Kito ni tsugu and Kyokutou shiki have more snare beats in their OST versions.