For rescuing Aquatic in the predecessor, Aqua Bubble, more and more Aquatics
from around the world now needing you for rescuing them too. While the
predecessor had only one game mode, this game now offers four different game
modes (two real-time, two turn-based). The basic gameplay, however, is still
the same: Shooting an aqua bubble with the gun at the bubbles in the level,
combining at least three of a kind to remove them. If the bubbles reach the
water at the bottom, the game is lost.

The four different game modes are:

* Arcade is the same game as the predecessor. You have a point limit you must reach before the level completes. If you wait, the bubbles will move down in real-time. You can see at your water meter how long it will take before the level ends.
* Panic is the same as Arcade, except that it is turn-based: After firing a bubble your water meter will climb and when it reaches the top, the bubbles will move down a bit. When waiting too long the computer will perform an randomly aimed auto-fire.
* Puzzle is like Panic, except that the gun won’t auto-fire and the levels are not randomized.
* Recolor operates like Arcade, except that all adjacent bubbles of a newly attached bubble will take the color of that new attached bubble. So, either you remove at least three bubbles with a shot, or you will change the color of existing bubbles. This can be used as an advantage to remove big amounts of bubbles at once.

Like the predecessor, the game offers eight power-ups which bring certain
advantages like freezing the playfield for a few seconds. They can be used in
all game modes except Puzzle. The more levels you complete, the more power-ups
and colors (up to eight) will be available. Furthermore, the bubbles will move
faster.