After downloading, soundtrack would be located here: Steam\SteamApps\common\May\May Original Soundtrack
Soundtrack includes:

BackGrounds:
01. Seasons (Menu Theme)
02. Peaceful Morning
03. Just a Feeling Love
04. Always
05. Hopeless
06. Sad
07. Terrible Tension
08. Simple
09. Everyday
10. Joke
11. Dream
12. Estrangement
13. Anhedonia

Endings (Instrumental/English/Russian):
01. Illusion
02. Alone
03. Sins
04. May
05. Monochrome Sky