It's the Soundtrack of Tren0, in "320kbps MP3's"+"FLAC" format. Over 34 tracks, for over 1 hours of music by "Yu Wei"
Tren0原声音乐集，包含34首曲目，长度1小时8分9秒。音乐格式为320kbps的MP3格式以及无损品质的FLAC格式
作曲：余威

Don't listen to it until you have finished the game!
建议在通关游戏后再听以下曲目（涉嫌剧透）

Tracklist:
曲目：

01 - Beginning (2:07)
02 - The wonderful train (2:37)
03 - Many questions (1:59)
04 - Darkfall (2:28)
05 - Desert (1:33)
06 - No men die (0:57)
07 - Investigate (2:03)
08 - Result (0:32)
09 - Sand storm (2:01)
10 - Snowy mountains (2:47)
11 - The darkest cave (2:20)
12 - Crash (0:37)
13 - Childhood (1:23)
14 - Anxiety (1:42)
15 - The boundless sea (2:41)
16 - Derailment (1:09)
17 - Abyss (2:18)
18 - Room D (2:33)
19 - No end (2:07)
20 - Rising (2:00)
21 - A tour of stars (1:09)
22 - A tour of clouds (1:27)
23 - Power off (2:38)
24 - Misty mystery (2:21)
25 - The highest stage (1:57)
26 - Above the clouds (2:02)
27 - Everything gone (1:42)
28 - Endless (1:40)
29 - Into space (2:40)
30 - Unknown trip (3:49)
31 - Terminus (1:57)
32 - Treno (4:01)
33 - Return to the hell (1:03)
34 - Trailer (1:47)

It is just OST files.
购买下载后在游戏目录里的文件夹“OST”内查看