Simple but gets the job done. Few individual levels are difficult per se, but the flow that develops as you learn the patterns and strategies over many levels is satisfying.
This game is devilishly difficult. It demands perfection. I gave up in frustration partway through, but I still love the music, the world, and most of all, the little white pixel cat you play as.
Atmospheric - it expands beyond the boundaries of its small size with a dramatic soundtrack, the perfect color scheme, and most of all, eerie poetic dialogue form melancholic, mysterious characters.
It's nice to visit a diverse, friendly world with a robot exploring what it means to be sapient. It's kind of an uplifting Saturday morning cartoon version of Blade Runner.
This is the core of what I'd want from No Man's Sky. A contained exploration experience, with moments of true delight - I ate cosmic shrimp!