The background music is in the ogg/bgm/BGM folder. All the background music of Biochemical 4 should be in this folder. It’s not very clear which one is which. I haven’t listened carefully. The music can be played with KMPLAYER or Baofeng Video. If you are impressed by the original poster, you should be able to hear it. However, the music of the mercenaries is not very impressive, basically no impression at all.

The ADA spy seems to be st075