Your company has created an application for doing crossword puzzles. The target users are in the age class of over 65 years old. There has already been considerable concentration on creating screens that are easy to navigate and intuitive. It is a primary goal that the software be easy to use. View ability has been implemented with a revolutionary magnification ability based on moving a magnifying glass across the screen. The beta testers have still had problems using the application, particularly when trying to enter the letters into the squares.
Given this information, which area should you target for more complete testing?