In lieu of TOJam happening this coming weekend I wanted to look back at my last jam-made game.

Submarine game

Got to love early builds!

During the last weekend of January thousands around the world, participated in Global Game Jam. I was one of those people. As a design constraint for myself I opted to make an educational game about water in an historical or environmental context (all topics I obviously care about). 45 minutes before the jam began I decided to make a game about history – specifically a game focused on World War I naval combat.

If you’re in the Toronto area you should come on out to the Toronto Global Game Jam Arcade at Bento Miso May 3rd.

Why World War The First?

I’ve studied quite a bit about the Great War in my undergrad years; although most of that time studying I was focused on the political, personal, and the cultural ramifications of the war. Why not explore the gaps in my knowledge by making a game?

I’ve been conceptualizing a trench-focused game for some time and want to release it later this year. The trench game is meant to highlight the hardships and constant death of what unfolded on land, which is something I do know about. Fortunately I don’t know this from firsthand knowledge.

With all of this in mind I wanted to push my knowledge of the Great War through game design. I’ve also never made a game set on or in water, and I have to say the water we “made” is gorgeous.

Submarine game 3

Here we follow a torpedo en route to hit a ship (note the lack of textures on the ship).

What’s more, by making a game about u-boats in this war opposed to the better-known u-boat campaign of WWII it would save us time and effort. This was before the militaristic use of the radio and the advent of both radar and sonar (no need to build those in code). There was a smaller number of torpedoes that a sub could carry. To cap it all off, WWI was filled with really bizarre (to our modern world) notions of how to engage in combat.

Here’s a primer on how the Germans fought using their U-boats:

The Game

Luckily (for me) Ali’s team couldn’t make it, so the two of us joined forces. We got our game to a playable state during the jam and have worked on it since.

I thought it would be worthwhile to record some of the historical research and initial game design.

The game has the player taking on the roll of a German u-boat captain in the early stages of the war; which is before unrestricted submarine warfare was declared by the Germans in February 1915. As a result, it’s important to follow the rules of engagement of merchant vessels:

Part IV, Art. 22 of the Treaty for the Limitation and Reduction of Naval Armaments, relates to submarine warfare. It states as follows:[2]
In their action with regard to merchant ships, submarines must conform to the rules of international law to which surface vessels are subject.
In particular, except in the case of persistent refusal to stop on being duly summoned, or of active resistance to visit or search, a warship, whether surface vessel or submarine, may not sink or render incapable of navigation a merchant vessel without having first placed passengers, crew and ship’s papers in a place of safety. For this purpose the ship’s boats are not regarded as a place of safety unless the safety of the passengers and crew is assured, in the existing sea and weather conditions, by the proximity of land, or the presence of another vessel which is in a position to take them on board.

Which essentially means that a warship (in our case a u-boat) can stop a merchant vessel and search it. If war materiel is discovered then the warship can do one of three things:

  1. Take the ship and contents as a prize;
  2. Sink the ship providing the crew is safe in their lifeboats;
  3. Let the ship go.

The third option is not a viable option in most cases, and the first one is particularly hard for a submarine to accomplish. Within a u-boat There is no storage room to carry a crew just for the potentiality of capturing a merchant ship. Meaning that the only real option was to sink the ship.

It was here that the unique gameplay can be found. The player needs to balance the goals of the war (kill/stop the opponent) while following international piracy laws.

Essentially, the player cannot go around just shooting any ship they find; it’s a risk to just fire at any old ship. This means that the game has two parts to it: hunting and talking.

Submarine game 2

The buttons allow one to talk, fire, or return to hunting.


This part is what it says on the tin: the player explores the water (or lays in wait) to find a worthwhile target. There are multiple clues to figure out if a ship is part of the Royal Navy or if it’s a merchant ship.

The key to hunting is not to be seen. If the player outs themselves by speaking to a ship that can reveal their location….well, bad things happen to the player.


Once a player targets a ship they can choose to attack at anytime or try to maintain a conversation. It is possible that a ship the player thinks is civilian is just lying and will turn around for the kill. Considering the timing of our game, during the blockade of Germany, once the u-boat is identified by non-German ships their is no escape for the player.

Optional Gameplay to Add

I am not sure we will ever add these but thought I’d bring them up anyway. We’ll see what the reaction is at the TGGJ arcade.

The first element that is needed is better artificial intelligence for the ships. Due to time constraints we don’t have an AI system which would have the Royal Navy warships self-identify and hunt the player. Currently, the only weapon in the game is the torpedo and we’d have to add ballistics and their trajectory if we’re going to have the Royal Navy hunt the player.

One thing that would be interesting is to have the player accidentally take out friendly merchants. This is not entirely unfeasible as Germany and Britain traded binoculars for rubber during the Great War. The problem is that the game is already somewhat frustrating when talking to captains who refuse to talk, and this could just add further confusion.

More knowledge:

The Paris Declaration

The Paris Declaration

This game is also an educational game and as such I’m creating a learning document to accompany the game. Here’s some of the research I did explicitly for this game, please note I’m also working on another Great War game and there’ll be another post with even more knowledge!

More about prize rules of the sea:
Declaration of Paris
Original copy of the declaration

To give an idea of scale and the difficulty in distinguishing merchant and naval ships here are some example of the types of ships which uboats were targeting: