Developer: Matt Glanville
Platforms: PC, Mac, Linux
Price: $9.99 (on sale for $4.99)
Games have explored the skies and beyond. the flickering corridors of futuristic abodes and the candlelit halls of medieval castles. But few have let us explore below and experience the dark depths of the ocean. Even in Bioshock you were isolated from the aquatic world outside, but Luminesca lets you discover the mysteries and secrets beneath the sea.
developer's site, Desura, and other sites. Luminesca was recently Greenlit.