The game is set in an alternate reality where most of the Earth is covered with water and factions war for the remaining pieces of land.

After a global cataclysmal event, the world is flooded, continents have disappeared, and little landscape remains above water level.

[1] The game begins as Grey and engineer Polly Edison discover the Gothean air force is heading for the Emperean headquarters.

[1] After desperate attempts to strike at the heart of the Gotheans, Grey and Edison discover a secret power, personified by a character named Cerbera.

In the closing sequence an escape module is shown fleeing from smoldering ruins of the battle, indicating an open end in the story.

[1] In Aqua, the player commands an elite vessel to navigate a world filled with vast seas and scattered isles.

In combination with various guns and upgrades, the player can configure multiple setups to create their own unique play style.

The player can also employ AI controlled squads of elite watercraft, giving them various context orders to influence the outcome of battles.

Players attempt to obtain a higher score than their opponent by reaching checkpoints which randomly appear in the level and by destroying neutral vessels.

[10] Ryan Clements of IGN felt that not enough time was spent to explain the setting of the Xbox 360 version and its characters.

The reviewer for Official Xbox Magazine noted that its "combat and controls are quite good, and yet it feels a bit sleepy.

"[8] Reed gave high remarks in regards to the same Xbox 360 version's customization and upgrade system which when combined with its story gives it "a personality of its own.