Design.md

Design

Ishan Pranav's REBUS is a multiplayer space trading game.

Players

Players are either human- or computer-operated. To balance the game, every time a human player joins, a corresponding "twin" computer opponent also joins the game. The game is not turn-based, but every every action that a human player performs prompts their twin to perform an action. Thus, the number of artificial (AI) players is equal to the number of human players and, collectively, AI-operated players progress in proportion to their human-operated counterparts.

Objective

The objective of the game is to be the largest contributor of credits (the game currency) toward a Universal Project. To achieve their objective, a player can issue orders to units (spacecraft) under their control in real time: Some execute immediately, and others are asynchronous. Players can decide to contribute any amount at any time, but all contributing players are charged simultaneously at regular intervals.¹

Units

Each unit can carry one commodity, each of which has a unique mass. The mass of a commodity does not affect a unit's ability to carry it. A player can order a unit to jettison (and destroy) its cargo at any time.

Navigation

The game universe is a grid of hexagonal zones. In addition to an unlimited number of units, each zone can contain a star, an inhabited planet, an uninhabited planet,² or no permanent features. Each attempted move costs one credit per unit per zone.

Exploration

A player can order a unit to blindly explore one of up to six neighboring zones. Any information about the destination and its contents can be incomplete, unreliable, or outdated until a unit visits it.³ Units cannot visit stars, but can observe them from any of their neighbors.

Autopilot

If a player has previously visited a planet, they may enable the autopilot to automate a journey to it. The autopilot always travels the shortest route through non-stellar zones already visited by the player. If multiple "shortest" routes exist, then one is selected arbitrarily but deterministically. Even while autopilot is enabled, each unit visits every zone on the route before reaching its intended destination.

Conflict

A player can order a unit to retreat from future battles or to defend its zone. The player issues these orders before (but not during) a conflict. A retreat order assigns a unit a sanctuary zone - a non-stellar neighbor which the player has previously explored.

If one player's unit attempts to visit a zone that another player occupies, it is intercepted. Before entering the zone, it must stop and disable the autopilot.

Each occupying unit ordered to retreat travels to its sanctuary zone, unless another player already occupies it. In that case, the retreat action fails: The unit defaults to defensive mode and does not incur a fuel charge for the attempt.

The defending fleet contains all units in defensive mode, while the invading fleet contains all the units attempting to enter the zone.

If the invading and defending fleets contain the same number of units, a standoff occurs: The invading fleet holds its position and does not enter the occupied zone.

Otherwise, each fleet loses the same number of units (as a function of the smaller fleet's initial size). Units are destroyed in descending order based on the masses of their cargo.⁴

The larger fleet captures the remaining units in the smaller fleet and occupies the zone.

Commerce

Units can trade with planets within their zones.⁵

At inhabited planets, players can sell commodities that the planet imports and purchase commodities that it exports. Planet imports are abstract descriptions of products while exports are specific commodities (for example, one planet might import food in general while another exports apples - a specific type of food).

When a player purchases a commodity from a planet, the planet increases the unit price requested for future sales. When a player sells a commodity to a planet, the planet decreases the price offered for future purchases. Each planet has an unlimited supply of exports and limited demand for imports.

At uninhabited planets, players can accept and deposit cargo.⁶

Future considerations

Potential planetary facilities under consideration include

• terminals offering passengers as an alternative form of cargo (this facilitates colonization – players may accept passengers from inhabited planets and deposit them onto uninhabited ones to inhabit them or evacuate one planet and migrate its population to another; population size may have an impact on the economy, and passengers cannot be jettisoned; passengers have zero mass),
• banks that allow players to earn interest on deposited credits,
• shipyards that allow players to purchase units,
• embassies that allow players to negotiate government intervention in the planet's economic system (via price floors and ceilings),
• insurance agencies that mitigate the risks of exploration and conflict, and
• data centers that allow players to upload and download navigational information.

Footnotes

1. The server commits contributions weekly. ↩

2. "Planet" extends to any non-stellar celestial body (for example, a moon, dwarf planet, space station, satellite, or asteroid). ↩

3. Players might use empty units as scouts to avoid entering traps. Weaker players might exploit the vast universe size to escape stronger players' dominions. A "hide-and-seek" mechanic might emerge. ↩

4. Only one player may occupy a region at a time. Interception stances do not respect informal agreements, so deception is possible. Once a conflict is in progress, the interception stances cannot be changed. No conflict occurs without both parties' consent. By entering an explored zone, the invading player is acting aggressively and must face any potential resistance. Meanwhile, the stance system ensures that the defender decides whether a conflict will occur. When a player assigns asynchronous stances to their units, the orders remain effective even while the player disconnects from the server. Thus, the system protects inactive players from harassment. For the aggressive player, the risk of being ambushed by a superior force deters exploration. At the same time, exploration becomes inevitable as local markets become unprofitable. ↩

5. Since players and planetary markets determine demand, the mass of a unit of cargo is not necessarily associated with its value. And, since units carrying the most massive cargo are destroyed first, players might reserve some units to carry less expensive, more massive, cargo to avoid the destruction of more valuable commodities. This system exhibits no randomness and can indirectly facilitate cargo exchanges. ↩

6. Piracy is possible by accepting unclaimed cargo before its intended recipient. A "treasure hunt" mechanic might emerge. ↩