I gathered the video links of the opening and ending song. 

Full OP song is now out as of 17th of December.

OP song by 時速36km called ''Around I'' ->

https://www.youtube.com/watch?v=b3Zur_tz_70

Ending song by UNFAIR RULE called Umio/内緒 -> 

https://www.youtube.com/watch?v=yTqD9H6KaEY

OP song by 時速36km called ''Around I''  preview->

https://www.youtube.com/watch?v=fmfgAiWGDzU

do you have any idea where we can find the scores/instrumentals for some of the BGM? that little piano tune that plays during the mirror temple scenes/some sentimental scenes was so good and calming to hear tbh