SNKRX for me. Minute to minute gameplay is very simple – all you do is steer your train of dots left and right around a small arena, but the depth of strategy and the skill cap is surprising. I got many hours out of it. Also there is a mobile version!
I played this after losing both of my maternal grandparents within weeks of each other a couple years back (they were both in their mid-90s and one of them brought COVID home) and Spiritfarer really helped me process my emotions and get through everything. Some of the characters reminded me of them in various ways, which was touching and cathartic. What a beautiful game.