This is a classical get-rid-of-all-blocks game.
You may encounter the boss or irregular ones.
How fast is your reflex?
How to play:
Touch the line in the lower screen.
You will have your little bar to hit a ball back.
iOS 7 note:
You may experience a slow response in the lower part of the screen.
You can fix this problem by turning off "Access Within Apps" in your iPhone.
Settings >> Control Center >> Access Within Apps