Pianoman
Japanese title: PIANOMAN
Type: ONA
Episodes: 1
Source: Original
Genres: Fantasy
Studios: Echoes
Duration: 5 min
Rating: PG-13 - Teens 13 or older

The still, white space expands as far as the eye can see. A man who's lost his memory awakens. An enormous door stands before him, and there's an old temple in the distance. The building seems to be calling to him, and the man approaches it. There's an old piano there. The moment he touches it, horrifying memories return to him. Who is this man, really? And what is the truth of this space...?

(Source: YouTube)