There are three types of promotions in the game currently. 1 extra life, 1 extra perk slot, or an extra starting perk (chosen randomly from the uncommon perks). It chooses two for you to pick between. The downsides are either double reroll cost, double exit cost, start with a loan or ban 5 perks at random. We are probably going to be replacing these systems soon though so you might not want to spend time working on it.
The promotions themselves are not really that hard to make, it is quite literally just printing a couple extra cards.
The main issue is with the banned perks. I could not figure out how to randomly determine them with a d100, or just 2 d10 rolls. Due to math being hard, the only thing that is not truly physical is the calculator for the game. Double Exit Cost and Double Reroll Cost are just number increases.
