The following is an excerpt from the Designer Notes for Offworld Trading Company. The game, an economic RTS set on Mars, releases on April 28, 2016, and is available for purchase here.

Although the black market is one of the defining features of Offworld, it was not part of the initial game design. The idea originated, after the basic free market gameplay was already in place, from an offhand comment made by one playtester — “It would be cool if I could sabotage the other players’ buildings.” The game was not supposed to be about combat (although in this earlier version of the game, the player could hire pirate ships that flew around attacking units and building), but some well-timed sabotage sounded interesting and fun.

The first question was how players should acquire sabotage. The idea of something called a “black market” fit well with the economic theme of Offworld. Initially, the Black Market was actually a neutral building that appeared on the map, which players could discover during exploration and then access to buy the items. (An equivalent Pirate Haven building existed for hiring pirates.) Each time a player bought an item, he would then be locked out of the market for a specific period of time, so players couldn’t sabotage as much as they could afford. (Under the original model, if a player found more than one Black Market, they could buy sabotage more often.)

We were also concerned about players turning an economic game into a de facto military one by deciding to spend as much money as possible hurting each other with sabotage. Therefore, we decided to double the price of each item every time it was bought by any player. (Eventually, this algorithm became a little more nuanced; the price went up by less than double, scaled by the number of players, and also increased for the purchasing player slightly more.) This global increase in price meant that, at some point, the cost of sabotaging another player would be so high that it would no longer be worth doing. Increasing prices globally had another interesting effect; seeing a Mutiny go up in price means that everyone knew that someone just bought one. Who is going to get hit? Which building? Maybe a player should buy a Goon Squad to protect his Geothermal Plant? Of course, once the player with the Mutiny sees the price of Goon Squads increase, maybe she should be more careful where she attacks?

The visibility of black market prices created a wonderful sense of paranoia, and we wanted to ratchet up the level of distrust among players by also not revealing who actually triggered each sabotage incident. When a Geothermal Plant gets destroyed with Dynamite or stolen with a Mutiny, the owner can only guess who attacked him. Hearing inaccurate accusations fly back and forth during play sessions is a singular experience. Players will sometimes engage in crude diplomacy by declaring who they think should be targeted (and why they themselves, of course, should not be). The fear of players aiming to knock out a specific players based on his pregame reputation led to the idea of the Masquerade mode, which hides a player’s identity until he is either eliminated or wins the game.

Originally, the items on the black market were the same six every game: Bribe Claim, EMP, Power Surge, Statis Field, Mutiny, and Underground Nuke. The Stasis Field, which froze ships in place, was cut when the Pirate and Police ships were removed from the game. To replace Pirate ships, two new items were added to the black market that had similar effects but no micromanagement – Pirates attacked shipping lanes and Dynamite destroyed buildings. After playing with this set of items for months and months, we were worried that players had no way to protect themselves from sabotage. Thus, we added the Goon Squad as a check on too much black market aggression.

We launched on Early Access with these seven items – Bribe Claim, EMP, Power Surge, Underground Nuke, Mutiny, Dynamite, and Pirates – which long-time players still think of as the classic set. However, after many more months of play, we felt that we were missing a great opportunity to add diversity to the game (and thus encourage more adaptive play) by adding more items to the black market and choosing them randomly before each game. Eventually, we added twelve more items to the black market, from which around seven are chosen each game.

Initially, the algorithm to select them was quite random, like picking cards from a deck, but this method made the game too random as the delicate balance between each type of sabotage and the other game mechanics was lost; for example, a Scientific player didn’t have to worry about Pirates or Magnetic Storms if neither one appeared for sale. Thus, we added some rules to govern the black market — there would always be either an EMP or a Power Surge, either a Dynamite or a Mutiny, and either Pirates or Magnetic Storms. Further, Goon Squads would always be in the game as long as at least two items which triggered them were available. These rules helped preserve a bit of the flavor of the classic black market, so that players have a sense of which items are more common and which are more rare.