First off, if you loved Simogo's other hit, Device 6, you will love this game. If you didn't like Device 6, you will still love this game (as long as you have a respect for puzzle games and care more about thought and strategy than mindless tapping).
As some other reviews have mention, there's a lot of depth here. And they're right. There are TONS of little hidden secrets. One example of this is if you hold on the "Spl-t" title screen you can play a mini-game where your balancing a ball. There's much more but I think I'll let you figure that out for yourself :)
On the surface, this game looks simple. You tap squares alternating the type of line you break. At first glance this game with its simple design, ironically has a lot of rules and looks complicated but once you start to get the hang of it you can't put it down (Also if you shake the device it can change the color if you ever get bored of the normal 'black and white' theme, and if you flip the screen over you can invert the colors). The goal is to get the highest score. Surprisingly, there are TONS of possible strategies to this game, and it's just one of those unique games you can't get enough of.
Remember, don't quickly disregard the game because of its early frustrations and huge learning curve.
All in all this is an amazing game that is easily worth the $2.99, all it needs it time and it will become your new favorite game.
Have Fun :)