Hello, thank you so much for playing. I'm really happy to hear you like the soundtracks!
Those are original soundtracks made by zensen, which I commissioned for the game. They're, for the moment, not available anywhere than in the game.
The only soundtrack you can listen to is the one from the Playtime Scene, which is a free to use track: Dancing With Congress.
Since you enjoyed the soundtracks, make sure to support the composer. He also creates vocaloid musics.
The other soundtrack you can listen to for free is the one in the park, it is free-to-use on Pixabay, I can share it to you if you want.
Thank you again for your interest!