http://www.bit-blot.com/aquaria/
(It's also available on steam for you achievement whores)
Basicly, it's an awesome indie game made by 2 people over a period of...
2. YEARS.
And it shows. It's amazing. The gameplay, the graphics, the environments, the music... it's all amazing.
AND THE MAIN CHARACTER HAS A BRITISH ACCENT.
Seriously, buy it right now. It's $20, but it's worth it. Hell, I'd pay $40 for it.
Also discussion thread.
I got it with the humble indie bundle, didn't really play it until now. Oh man do I regret not playing it before.
I'm up to Open Waters after the [SPOILERS I GUESS]energy temple.
Killing everything with the energy form makes me feel so terrible, and when the PC does that creepy laugh it sends shivers down my spine... D:[END SPOILERS I GUESS]