The game’s name is Deepsea. You control a jellyfish with the stylus and guide the jelly through a randomly-generated world, fighting enemies by colliding with them.

The current area is fairly small (5×5) and will probably be the world size on Easy mode. There’ll be enemies and bosses and other gameplay elements added in later.

http://dsgamemaker.com/forum/viewtopic.php?f=27&t=5068