Fluidity is a puzzle game for Wii. Its gameplay is based entirely around the Wii Remotes' tilt sensors. A magic book has been infected with a bottle of ink known as the Influence. In order to save the book from corruption, you must pick up the book in your hands and tilt it to move a source of water around its colorful pages.
You'll use this water to hit switches, collect gears and fish to open up new areas, and defeat the Influence's minions. In addition, tilting the book also controls various machinery, including a crane, a pinball machine, and a monorail.
The player uses the water to collect Rainbow Drops, which act as the main means of progression in the game. As more drops are collected, new areas of the book open up for the player to explore. The player also receives various powers along the way, such as the ability to change into solid and gas forms. Many of the raindrops can only be collected after the player has received these forms and their powers.