Australia, January 9, 2008 - Aquaria is a game that revels in simple pleasures: in the joy of lithe movement in its underwater world; in exploring new and potentially treacherous areas; in slaughtering harmless fish. Indeed, your first half an hour with the game is almost meditative – swimming through caves and tunnels, mastering the straightforward movement controls, avoiding predators and communing with the surprisingly friendly jellyfish. It's a smooth introduction, and a mirror of protagonist Naija's heretofore solitary life. Who is she and what happened to her people? These are the questions that spur her on into the wider world of Aquaria.

Within its lovingly hand-painted environments Aquaria very much takes a number of classic game designs as inspiration. You'll see shades of Super Metroid and Castlevania in Aquaria's progression system, a smattering of Zelda in the song spells, and a decent dose of space shooter gameplay in its combat. That's by no means a bad thing, and indie developer Bit Blot – comprised of two guys – has done a great job pulling it all together (for the demo or to buy the full game, head to the website).

There?ll be no accusations, just friendly crustaceans, under the sea!

The most striking element as you progress through the game is the size of the world – it's absolutely huge, and comprised of a massive network of interconnected caves and tunnels, just begging to be explored. There's no linear path through this world, and by the time you're a few hours in you'll have access to several huge areas simultaneously. As you'd expect, however, the world is revealed in stages, with many paths and secrets locked off until you return with the requisite skill. In other areas currents push and pull you about, dictating where you can swim.

Initially a defenceless denizen of the deep who must out-swim anything threatening, it's not long before Naija earns her first transformation ability, which is triggered - along with other spells - through song. Holding the right mouse button brings up a radial menu consisting of a number of coloured icons, each associated with a note. Move the cursor across the icons in a particular order and Naija transforms into a being of pure energy – Dark Naija essentially. In this form she can fire off streams of energy and a charge up homing attack. Switching between the hunter and the hunted becomes a core component of the gameplay, as Naija is more versatile in her base form, but exposed. It's only in her base form, after all, that she can cast spells, so clearing away rocks to reveal a path, or harvesting fruits from plants brings with it an element of risk in more dangerous waters.

A fish, a fish, a fish, a fishy oh. That went wherever I did go!

The controls are largely very good. Naija can navigate the waters entirely through mouse control should you wish. Just hold down the left mouse button and move the cursor to guide her, or you can click at a distance to dash in that direction. There's also direct control using the old WASD config, and we found ourselves using both. Combat in Aquaria can get quite hectic – some chambers are filled with predators chasing you and firing off projectiles, so the ability to directly control Naija through the maelstrom, while shooting and aiming with the mouse, is an important option.

Controls aren't perfect, however. We found the dash move – which is also used to dash and grip to walls – a little frustrating. In enclosed spaces we found ourselves leaping from wall to wall when all we wanted to do was move through the area at speed. Despite this small niggle the sense of gliding and smooth movement has been captured fantastically well. There are also other nice touches in the controls too, such as the ability to spin the cursor around Naija to create a whirlpool of sorts. Very handy for clearing off the hard-shelled little creatures which occasionally attach themselves to Naija and slow her movement.