From The Depths price comparison

In From the Depths you can build and take first-person command of battleships, planes, submarines, giant terrible geese, space ships, hot air balloons and more! The game is currently in alpha and contains a wide range of single player content including:
A creative mode allowing you to push your designs to the limit and ensure the total annihilation of your opponents.
A campaign waged over hundreds of islands against eight unique factions.
A Story Mode where you can (eventually!) play 15 missions as each of the eight factions - a fantastic mixture of strategy, design and wild battles! Defend your fleet against waves of enemy forces in a series of extremely tough challenges that unlock new components.
An expansive multiplayer and co-op element is planned for the coming months!