エキストラトラック詳細 [Extra Track Details]
15 ブランクトラック [Blank Track]
16 RAIDEN DX UNUSED SOUND
基板ROMに残っていた、[Remaining in the ROM]
雷電DXの未使用サウンドです。[Raiden DX's unused sound]
17 RAIDEN PROJECT OPENING TAKE02
3ループ目の曲テンポが早くなる完全版を収録。[song tempo becomes faster, complete 3 loop version recording]
18 RAIDEN PROJECT PS LINE REC01
データと実機再生を比較してあまりにもテンポの違う曲を収録。[data and real machine playback recordings have different tempo]
こちらが実機再生のテンポとなります。[this is the real machine's playback tempo]
19 RAIDEN PROJECT PS LINE REC02
同上 [same as above]
20 RAIDEN PROJECT PS LINE REC03
同上 [same as above]
21 RAIDEN DRAMS TAKE01
AC版 雷電楽曲のドラムパート01 [Arcade version of Raiden, drum part 1]
22 RAIDEN DRAMS TAKE02
AC版 雷電楽曲のドラムパート02 [Arcade version of Raiden, drum part 2]
23 RAIDEN SE
雷電の効果音集 [Raiden's sound effects]
24 RAIDENⅡ SE
雷電IIの効果音集 [Raiden II's sound effects]
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Does it say anything about the composers here ? And there is even more omake, on the last disc is a data track with design files for Raiden.
Yes indeed it is a fantastic set

INH loves the fans, and draining my wallet!
Nothing about composers in there. The identical family names seem to just be a coincidence(?) To my understanding, it should be that Akira Satou composed the tracks for Raiden (1990) and did the arrangements for the FM Towns version (1991). Later, after Akira left, Gou Satou was responsible for: composing Raiden II (1993), composing and arranging tracks for Raiden DX (1994) [see below], and arranging Raiden and Raiden II's music for the Playstation Raiden Project (1995). Also composing for Viper Phase 1 and the first 2 Raiden Fighters games, but that's a bit outside of the scope of this soundtrack.
A note on how Raiden DX's music is set up: it mostly uses Raiden II's music, but there are a couple of additional songs to fit the new game system (Course Select & Ranking), and there were also a handful of Raiden tracks arranged for the new sound hardware (level location is shown on the back insert of the set).