If you're a fan of Tetris, chances are you'll love Shades.
The basic concept of Shades is similar to Tetris: Match the falling bricks together to clear rows and avoid a massive pileup that reaches the top of the screen. The big difference is that Shades asks you to match bricks based on the shade of their color rather than the physical shape.
All blocks in Shades are the same shape, but they vary in the shade of their color. The goal is to match two blocks with the same shade, which merges the two blocks into one block of a darker color. Like Tetris, you tap on the screen to decide which column the block falls into, and swiping downwards speeds up its descent.
When you create a row of the same color, it disappears.
Shades has been out for a while now, but it's free for the next week since Apple has named it App of the Week.
Developer UOVO has done a great job with the overall design of the app, and the app's focus on color variation makes the levels pop with color.
The game's stellar orchestral soundtrack adds a pleasant atmosphere to the gameplay, and there's a satisfying sound each time two bricks meld together into one. When you lose, the soundtrack plays you off with a nice little walking baseline.