Awaken: Underwater Odyssey (2014)

Awaken: Underwater Odyssey is vertical scrolling shoot em up game. Game takes place in far future on planet Neptune. You are member of Kraken squad, which is stationed inside a Leviathan class carrier craft owned by RPE corporation which oversees gas extracting operations on Neptune. The game is about annihilating thousands of squid like aliens while you pilot an Orca MK II submarine which is highly customizable to fit your style.