I do not hand out the title of masterpiece very often or lightly. In order for a game to reach that level of praise, all the details and bits and pieces, the graphics, the writing, the art direction, the music, the gameplay itself... everything has to come together to form a unified, cohesive whole.
I can say with absolute certainty that Outer Wilds meets that criteria. Is is beautiful, elegant and inspired. It's impossible to really explain why without spoiling it, and this game is uniquely susceptible to being spoiled.
The only downside is that once you have played it once, you can never really expience its full potential again. Again, it is impossible to explain why without ruining it, but its still well worth playing. Do yourself a favor and go play Outer Wilds!
