Getting hardware gimmicks right is a tricky thing. Most of the time, whenever a game makes heavy use of hardware-specific features, it feels tacked on and out of place. Every so often, a game developer does something innovative with those features, and the result is a flash of brilliance. Such is the case with Fluidity: Spin Cycle on the Nintendo 3DS.

A sequel to the Wii original, Fluidity: Spin Cycle has the trappings of a platformer, but it's a puzzle game at heart. The goal in each level is straightforward. You must rescue the trapped Rainbow Spirit from the evil Goop. You'll do that by flipping switches, jumping across platforms and moving items from point A to point B. The thing is, you play as a water spirit, so instead of moving around on legs, you flow based on the power of gravity. That's a fancy way of saying that you're a puddle.

Because you're a puddle, moving around with the analog disc isn't really an option. Instead, Spin Cycle uses the system's gyroscope for movement. Tilting the system to the left or right causes the water to flow in the corresponding direction. Certain levels feature a full 360 degrees of movement, which means you will be holding the 3DS upside-down at some point. Reading about it on paper might sound unwieldy, but it's surprisingly intuitive. The illusion of movement is done so well that we occasionally found ourselves shaking the 3DS in an attempt to knock a specific item loose.

In addition to the gyroscope, Spin Cycle also makes use of the buttons and the touch-screen. Shoulder buttons are used for jumping (though it's more akin to tossing a cup of water in the air), while the face buttons are used for actions, such as flipping switches or collecting yourself into a pool. Actions can also be performed by pressing virtual buttons on the touch-screen.

One interesting thing is that Spin Cycle very specifically does not support the 3-D function on the 3DS. As soon as you fire up the game, 3-D is disabled. This isn't a mistake on the developer's part; rather, it's a smart move. Anyone who's played the 3DS will tell you that the 3-D effect requires your eyes to be in the sweet spot for it to work properly. For a game like Spin Cycle, which requires moving the system, any attempt at 3-D would quickly result in a blurry mess — and perhaps a headache. Kudos to Curve for knowing which system features to ignore.

The puzzles in Spin Cycle start out basic enough, though the difficultly level ramps up at a steady pace. As the levels get more difficult, more tools are at your disposal. For example, early on in the game, you gain the ability to "explode" yourself and push blocks a short distance. In certain areas, you can freeze yourself into a solid block. Later on, you can turn into a mist. Enemies also increase in complexity, with the first goop being little more than basic targets. The next step up adds a temporary flame to the goop arsenal, forcing you to time your attacks since fire will evaporate water.

Replay is encouraged in Spin Cycle, as each level features a star rating. There is also a hidden puzzle piece. Star ratings depend on collecting the water droplets within a level as well as finishing quickly. With that said, Spin Cycle doesn't punish players who take their time. When the level timer runs out, the level doesn't end, and you don't die. All it means is that you don't get the star for finishing quickly. This helps ensure that Spin Cycle is accessible to players of all skill levels. It also encourages players to explore during their first time through a level. You can always speed through later.

Finding the hidden puzzle piece in each level requires a keen eye, though it can also require use of specific powers. Thankfully, once a power is unlocked, it is available for use in any level. This is important since some puzzle pieces cannot be accessed the first time you visit a level. Once you collect all of the puzzle pieces, you open up a bonus level designed as an obstacle course.

It would be easy to dismiss the game as a one-trick pony, but to do so would be a mistake. Yes, it makes heavy use of a specific hardware feature, but it's so well integrated into the gameplay that it doesn't feel like an afterthought.

Easy to learn and difficult to master, Fluidity: Spin Cycle may be an eShop exclusive, but it looks and plays like a full-fledged retail release. If you have even the slightest interest in physics-based puzzle games, add this one to your download list ASAP.

Score: 8.5/10