I played in Chrome just to see and it looked and ran beautifully. I'll try a download build later to see the difference, but this was a wonderful experience.
I think the sound design is top notch and for a game without art, it sure is beautiful! I like the subtlety of the story, the chapter breakouts and the achievements felt so good as a gamer. I do think you should have collisions with the walls because I thought I was really clever with "listen to the darkness" so I thought going off the game path and toward the darkest part of the screen I would find some unlock or new story, but then I came back and read Spoonsweet's comment and your reply and realized the path is the intended path and just to stay in bounds.
I agree you need a spacebar prompt to interact, when I ran the game I was taken away from the itch.io page so I had to check again to see if there was a button prompt for dialogue. After that it was a wonderful experience.
Are there multiple endings? I thought I was supposed to be finding the ball and uniting the father and son with it, but then I ran into, I guess "her", and then we made up and the game concluded.
Really impressive entry. Such a great experience and just the right length. And you provide two language options!! Great work, as always.