HMS Marulken is a co-op simulation game in which a team of players operate a Swedish World War II submarine. The game is played over local network or the internet on PC and Mac. The players connects to a server, where they choose a submarine to serve on. Each crew can consist of up to four players, manning the stations in order to operate the ship.

HMS Marulken started as the final project for our bachelor’s degree in game development at the Department of Computer and Systems Sciences at Stockholm University. The game was originally intended as a small and simple project, but we decided to develop it further. We went from 2D to 3D, and decided to use Unity instead of our own engine.

We got the idea for the game when we played Artemis Space Bridge Simulator, which is an unofficial Star Trek game, where a team of players control a spaceship together. At the beginning of the project, our game was primarily meant to be used on tablets and mobile phones, with a simple point and click interface.

The game has gradually evolved into a full 3D game with free movement and FPS-like controls. The biggest challenge has been to figure out how the game should be played, ie how to design a submarine game for four players that feels believable while still fun to play.

Since last year, we have developed the entire game from scratch in Unity 5. All scripts, models, textures and sounds are new. Instead of fixed positions, as in Artemis, the players can move around freely on the submarine, like in Guns of Icarus. We've added the ability to play with multiple submarines on the same server. It is already possible to play the game cooperatively, and we are now working on implementing PvP modes. We have also added radio communication, aircrafts, a deck gun, a torpedo data computer, as well as the first level in a story-driven campaign.