FallingUp is an original puzzle game a la Tetris in which you must place the falling blocks in a way to form lines and score points. The objective of the game is to advance as much as you can by creating lines. Every level has a certain number of lines that you must form in order to advance to the next one. What makes this game original and very challenging is that, from time to time, the board flips, moves around, and spins as you are playing. Even with these board changes, you must continue playing as you can. As you advance in levels, these changes will come more often and the blocks will fall faster and faster.
You cannot save games, but you can start from the level you want. Moreover, if you want to make the game even more challenging you can hide the next piece, so you don't know what block is coming. The game features very simple graphics and sadly, no music, but it has pleasant background sounds of water flowing.
In short, if you are looking for a simple and challenging tetris game to pass the time, FallingUp may be a good choice.