The Ludum Dare 29 game jam is currently in the voting phase, with the theme "beneath the surface." Developer Sebastian Janisz of Ultimate Walrus took the theme to a decidedly less mental place than some of his past creations, where the player controls a submersible vehicle as it travels down into the sea near a coral reef. Despite the decrease in wackiness, it looks cool.
With its isometric view, parts of it almost remind me of the crate puzzles inside the pirate ship in Super Mario RPG. At its core, it is a shooter (poor jellyfish), but what makes it unique is that it allows for three-dimensional traversal inside its two-dimensional engine. Though his game jam entry is available as freeware, Janisz wants to flesh the idea out into a larger game soon.