The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
On or Off is a problem. Your problem is: Try to turn on or off the lights to make them all on or off.It's a brain training game. A good game to kill time.Click on a light to turn on or off vertically and horizontally adjacent lights. When all the lights are same on/off status, you will be enter the next mission.Don't hesitate,let's play the game.