Added a launch screen (timed 2s)
Added an app icon
Added custom branding and visuals
Two additional screens (receipt + change credit card)

Some UX thoughts: I had the idea to turn this app from a simple tipping
calculator to something of value to both businesses and customers.  The
idea is that you can pay within the app, and giving tips gives the
customer rewards.  Of course, haven’t implemented it all, but you can
see elements of it in the latest design.