Tidalis is a block-based puzzle game with casual appeal, hardcore depth, and an addictive new "streams" mechanic. The basic rules of the game are this: blocks fall down into the board and have a color and an arrow direction. If a stack of blocks exceeds the height of the board, you lose. In order to clear blocks, you must right-click and drag paths through the arrows to set up chain reactions of like-colored blocks.
This official release includes a lot of new stuff for players to enjoy, a lot of it suggested by fans. It adds the new VS - Race multiplayer ruleset for use against the AI or against other players, as well as a new Boarded Up block type. It has a lot more flexibility in what fullscreen resolutions players can use, even if their graphics card/OS doesn't report a resolution that they want to use as being supported. There is also a revamped sound subsystem that lets the game load faster, play multiple copies of the same sound effect at once (which sounds much better), and which avoids some issues on OSX.