Hi. I bought Aquaria after having played Dive: The Medes Islands Secret from Big Fish Games. That game was lots of fun. I enjoyed exploring the depths of the ocean and discovering the secrets. It has a good story, but it's not as long and complex as Aquaria's.
I started a new Aquaria game because I played for a few hours, got sidetracked, and forgot the beginning. I've just been swimming around the Turtle Cave. This is currently my favorite game! The art, music, and story has captivated me! I'm not very good at the boss fights, so it's taking me longer than it would for most people to progress. I'm guessing I've made it halfway through (?), and I've played a total of 25-30 hours, including the first game I started.
This game is so immersive and fun that I've decided to recommend it and buy it for my future daughter-in-law. I'm surprised the forums aren't busier. I read somewhere that the game wasn't a successful venture for the devs. What a shock! The game is fantastic. I wish them all the best, and I sure would like to play a sequel. :-)