If you've ever had a nightmare where you're being chased by some unknown entity through an ever-rotating tunnel while constantly terrified you might fall into the void then you already have a rough understanding of Twist. Unlike other more passive games, this one (which comes from the same developers behind 2048) is a nonstop ride that keeps you on your toes, and may very well lead to some audible outbursts in public.
As much a feast for the eyes as it is a test of your motor skills, Stack challenges you to, well, stack rectangular planks -- swinging back and forth like a pendulum -- flush atop one another by tapping them the exact moment they pass over the increasingly tall structure. It gets harder and harder the taller you go, as every edge you don't match up precisely is shaved off until you run out of any surface area at all. Good luck trying it just once.