2048 is an Android version of the great puzzle game by the same name. What you have to do is move and combine numbered tiles around a board, with the goal being to create the highest number possible.
Every time you move a tile in any direction, you get a new one with the value of 2 (or more, as you advance). When you combine two tiles of the same value, they turn into a new tile with the combined value of both. For example, if you combine two tiles with the number 32 on them, they become a single tile with the number 64 on it.
With this gameplay in mind, you have to try to get the highest score possible, which you can get by combining tiles until you reach the value of 2048 (hence the name of the game). That said, this is an achievement that very few players ever manage to reach.
2048 is an excellent Android version of the great puzzle game by the same name. Plus its control system is perfect for touchscreens.