If you're wondering where to spend those Nintendo Points burning a hole in your pocket, look no further than "Fluidity." Downloadable through Nintendo's WiiWare service, this little platform-puzzler is drenched in fun. Like its brilliant fellow WiiWare game "And Yet It Moves," "Fluidity" feels like a Wii launch title -- not because it seems like a prototype, but because its concept is so elemental and well-suited to the Wii's capabilities that it's amazing no one has thought of it before. Tilt the Wii Remote to one side or the other, and the game world tilts, sending a small body of water sliding and splashing around with convincing physics.

This little puddle is on a mission to collect Rainbow Drops to clean up its elegant storybook world, and it's your goal to direct the water in a way that keeps it all together, losing as few drops as possible behind to dry up. The 3-D "Mercury Meltdown Revolution" tried a similar concept earlier on the Wii, with droplets sliding into oblivion when your mercury bead teetered over the edge, but never found anything fun for you to do with the mercury itself. Contrast this with "Fluidity," which starts you off filling buckets to manipulate pulley systems, and before long presents contraptions that turn your water to ice or steam as befits the situation. The world of "Fluidity" is pretty and playful, but has the kind of uniform logic that invites experimentation. It's like a science fair, but fun.

Add a smattering of clever minigames and you have a title that sits just below the Gamecube's "Super Monkey Ball 2" in the pantheon of gravity games -- and it's certainly tops in the broom closet of offerings of this kind on the Wii.