I don't see how people can be addicted to such a repetitive boring game that took only a day to make.
It's psychological. The challenge posed by the game creates frustration, which in turn makes the player want to solve the challenge all the more, creating more frustration. It's a devious and vicious cycle.
It is an example of the success of organic advertising, as the creator did virtually nothing after uploading the game.
Not to mention its popularity soared when students in my country are in the middle of midterms / thesis / final pre-graduation season. Satan is a fucking genius.