Hook, the highly acclaimed minimalist puzzler from Rainbow Train, is currently free on the Google Play Store.
Originally released in 2015, Hook sees you clearing a succession of screens by adjusting and tapping nodes to make various shapes disappear. It sounds easy, but these shapes are attached to lines that intersect and overlap, forcing you to plot your moves carefully.
Embracing its minimal theme, Hook lacks points, stars, leaderboards, power-ups, timers, and all the other paraphernalia that characterize modern puzzle games, for better or worse.
If its user reviews are anything to go by, the minimal approach works. Hook is sitting pretty on a highly respectable 4.5 stars from almost 30,000 reviews, and you can download it for free right now.