You're a captain on a little submarine. 

Your goal. Try to go deeper and deeper into the ocean to retrieve the ocean's treasures to upgrade the submarine to eventually reach the bottom of the ocean.

But we warned. Your supply of oxygen is limited and you need to use the treasures you find along the way to upgrade your oxygen supplies.

Good luck captain.

Controls: 

Space/Press on screen: Submarine goes down.

Do nothing: Submarine goes up.