More to think about

Why is the shift button called “shift”?
Why is the space button so much bigger? Do you press it with your thumb?
All your keys are debounced on the electrical level…
…but actually you could debounce your buttons on (say) your webforms (no human can mean to press “pay” within 500ms of the last time, right? Are you checking for that?)
Why do the keys have CAPITAL letters on them when most of the time you’re getting lower case?
What’s a key-logger?
What’s a Dvorak keyboard?
In JavaScript in your browser… can you detect when the left and right shift keys are pressed — and tell which is which?
What about the number pad numbers versus numbers from the “regular” number keys?
If you write a program that handles events, what are the differences between keydown, keypress, and keyup? How do you decide which to use?
Do you know how to type £? Or ” or Ø or ♥ or ½? Why might it be a bad idea to have characters like these in passwords?