I came in thinking I would nominate Pathologic: The Marble Nest, but I don’t think it’s available for download on Steam anymore (and technically it is only an alpha demo, really). Still, I just want to shout it out for being a fucking incredible experience in spite of its only being around three hours long and carrying some jank. Sure as shit got me excited as hell for Pathologic 2 sometime next year.
Anyway since I can’t rightfully nominate that, I’ll just add to the cacophony of voices saying Zelda: Breath of the Wild, because that game devoured me and never quite let go. It has continued to not let me go in spite of beating it, because I can still boot it up and within like five minutes be sunk deep in a world making discoveries of stuff that I haven’t seen before, or just taking in what is a downright gorgeous world (even though the framerate could be better in places).