Add some extra messages of your own. Make sure that you test them before putting them into the final program.

See if you can improve the way that the messages appear. At the moment the screen is cleared and then the message appears instantly. Try to change show_message so that each character takes longer to appear. You can do this by using a call to the delay function in between printing each character.

For extra artistic effect you could make the program print a number of random characters before printing the correct one at a particular position. If you do this remember to put the cursor back to the correct position after each random character.