A pocket UI is a timeline, not a wall
People do not 'enter' a mobile UI like a website hero. They glance, look away, glance again. The design must support that staccato mind.
The first glance should answer, 'am I in danger of wasting money by accident?' and 'is this the same game I opened yesterday?' If those answers are not immediate, a player can feel a subtle shame—like they are stupid—when the system is the thing that mumbled.
A second glance can carry nuance. But if the first glance was noisy, the second will never come. The Frame Theory team prototypes with interruption cards: messages that pop on schedule during paper tests, because fiction without interruption is a lie about mobile life.
Typography on glass is a different sport than typography in a PDF. Test on the cheapest phone in the office, not the review device you love. If a help screen only works on an OLED with full brightness, it is not help—it is a showroom trick.