This is Remembering. It's a "poetic exploration game driven by sound". It's finished and available for download here. You should go ahead and do just that.
It's a wonderful little experience. By stripping away all but the most basic visual elements, the game - and your interpretation of its world - is powered mostly by sound and music, as you explore stages experimenting with music and keeping an ear out for the changes that slowly bleed into the soundscape.
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Remembering recommends you play it with headphones. You really need to play it with headphones.
Remembering [Game Site]