Simon is a mobile version of the popular Simon Says electronic game made famous in the Eighties, when it was the closest thing many people had to a modern day video game.
In case you've never played it, the object of the game is to match the pattern of flashing colored lights displayed by Simon. For every pattern you remember correctly you score one point, and if you get enough points you can move onto the next level.
Simon is still as interesting a challenge as it was thirty years ago, and is great for improving your powers of pattern recognition. However, this version is fairly basic in terms of its presentation and gameplay. There is only really one screen and one game mode, so if it's variety you're after you've come to the wrong place. There is a high scores table though, which will keep you coming back for more for a while in order to break your record.
Simon says: "install this program". I say: "install it if you want but it's nothing special".