Basing a 2D platforming puzzle game on a substance as familiar as water might not seem like the most inspired of ideas, but the more time you spend with Hydroventure--known as Fluidity in the US--the more you realise how great it is. Like the water you control, the puzzles you solve have a flow, effortlessly merging into each other to create an experience that always challenges you yet never makes you feel stupid. These are brilliantly designed, each of them guided by the real-world physics of water, making them immensely satisfying to solve. While the difficultly does take a sudden, and frustrating, spike upward toward the end, it's not enough to detract from this intelligently designed and beautiful-looking game.
Hydroventure takes place inside a magical book known as Aquaticus. Life within is usually a peaceful affair for the water inside, but a malicious inklike goop known as The Influence has decided to take over, destroying everything contained within its pages. This presents a problem for the book's spirit, which calls upon you as a sentient pool of water to traverse the book's pages and destroy the evil Influence. To navigate your way through, you move your pool of water by tilting the Wii Remote. Instead of moving the water directly, the pages of the book tilt, as if you're pouring the water from one side to the other. To make it jump, you jolt the Wii Remote up, as if you're shaking the book. This indirect control might not be as accurate as simply pushing buttons, but it feels just right, with resultant splashes and stray drops that dance around the screen as you move.
Keeping those stray drops together is the key to making your way through each of the four chapters of Aquaticus. Puzzles start as simply as pooling the water into wells to activate switches, dragging cogs to repair machines, or providing a temporary shelter for stray goldfish as you get them back to their bowl. Complexity rises as elements like water pumps and moving platforms are introduced while such obstacles as lava pits, fire-breathing blobs, and flying creatures that rain down fiery bombs try to evaporate your precious water and end the game. As you solve puzzles, you're given new powers that further increase the difficulty. You can pool your water together at will, where it gradually increases in pressure and explodes to break down obstacles in your path. Later, you can turn into an ice block that sticks to surfaces or a cloud that can float to previously unreachable areas and launch lighting strikes at enemies.
These three forms are used to create devilishly fiendish puzzles. For instance, one puzzle has you transforming into ice to break down barriers in a path, after which you have to transform into a liquid to travel across moving bucket containers before going back to ice to pull down a heavy door with your stick ability. Once there, you transform into a liquid to release a cog, use ice to activate a switch that raises the cog on a lift, and then finally move back to a liquid to transport the cog through the bucket containers to repair a broken machine. The large variety of puzzles means you're always treated to something new. As you progress through you help firemen to extinguish fires, play delicate balancing acts with weights, and even help a spy to deactivate a nuclear weapon by destroying security cameras, to name but a few. While the solutions are sometimes tricky, they always make sense and are immensely satisfying, as well as heaps of fun to solve.
Your reward for solving puzzles is a rainbow drop, of which there are several scattered across the four chapters of Aquaticus. The four chapters span multiple pages, with each page separated into comic-book-style panes. This allows the game to use different themes from pane to pane, including the Serengeti, vast skyscrapers, and the rolling hills of the countryside, without ever feeling out of place. Charming details such as the chug of a steam train or the statues of an Inca village make the backdrops come alive, with the crisp and colourful art style making them a joy to explore. Not all panes are accessible at once, however. Some require you to collect a certain number of rainbow drops before you can access them; others aren't accessible until you acquire a new power, encouraging you to explore each area multiple times to uncover new puzzles.
Once you've collected enough rainbow drops, you can face off against The Influence by destroying its minions on a specially designed level, where you're rewarded with a new chapter for your efforts. These are the most challenging levels of the game, requiring some deft Wii Remote skills and a lot of patience. While the first three are ultimately rewarding, the final level is punishingly difficult, with cheap moving platforms and fire pits. You may find you don't have the will to see it through to the end, particularly as there's little reward for doing so. There's also only the Story mode to play through, with no multiplayer or even simple leaderboards to compare scores or completion times against friends. This isn't enough to detract from what is a fantastic experience, though, with the story mode featuring tons of hidden puzzle pieces and flowers to collect. These unlock minigames, such as pinball tables and one in which you have to save goldfish against the clock. Secret rainbow drops also ensure that you can spend hours exploring each level multiple times to find new puzzles to solve.
The vast collection of hidden content means that there are hours upon hours of well-crafted puzzles in Hydroventure, while the mixture of fun ideas means the core concept of moving a blob of water around never gets old. The way each chapter is laid out into separate pages and panes not only allows for some diverse and great-looking visuals, but it also means casual players can easily dip in and out for short bursts while more determined players can spend longer amounts of time hunting down extra content. The final level might be a bit too much for some to stick with, but that shouldn't deter you from playing this excellent puzzle game, one that any Wii owner shouldn't hesitate to splash out on.