Failbetter Games is working on the first expansion to Sunless Sea, titled Zubmariner. With the expansion, Failbetter is looking to add a new dimension to the game by going under the sea and has a trailer to show it off.

The early alpha footage showcases the sea floor, which players will be able to reach by attaching a zubmarine shell to their boat and diving. Lighting will be limited depending upon the depth of the water and allow for a limited amount of visibility of larger objects above the player.

Sunless Sea is a 2D exploration game where players command a ship set in the Fallen London universe. Those who want to learn more can read Zach Wellhouse's review here.