Simultaneous planning in games

Simultaneous planning happens when all players are giving orders independently at the same time, often without knowing opponents’ decisions at the time. The planning phase is then usually followed by the execution phase, where the game resolves given orders.

Use case

Simultaneous turns are mostly used in:

• games that include a huge number of players, like games from the autochess genre (such as “Teamfight Tactics” or “Super Auto Pets”)
• other wave-based auto-battlers (such as “Legion TD 2 – Multiplayer Tower Defense” or a “StarCraft 2” map called “Direct Strike”)
• team-based turn-based games (e.g., “Atlas Reactor”)
• games that want the strategic depth to have an unusual flavor (such as “Infinity Wars: Animated Trading Card Game” or “Random Dice: GO”)

Perks of simultaneous planning

Getting rid of the first player’s advantage problem

Usually, in turn-based games, the player who starts the match has some sort of advantage. Even if that advantage is mechanically compensated, the problem is usually minimized instead of being erased. Since simultaneous turns assume that everyone is doing turns at the same time, the concept of the first player doesn’t exist, meaning no player can get such an advantage.

Reduced waiting time

The annoying part of turn-based games is that you spend a lot of time waiting for decisions made by other players. The more players participate in a match, the more time you spend waiting for your opponents instead of playing yourself. With simultaneous turns, all players plan at the same time, but resolving orders still may be time-consuming.

Some games with consecutive turns use simultaneous turns situationally to make the gameplay a bit more convenient. An example would be the game “Heroes of Might and Magic 3”, where players normally take turns consecutively, but since they start the game on a huge map far away from each other, they’re free to take a few turns simultaneously until they get close enough to possibly interact with each other. It slightly speeds up the first turns of the game.

The art of reduced waiting time has been mastered by games from the autochess genre. The twist is that during the execution phase, each player is paired with only 1 random opponent in an isolated environment, meaning actions of other players don’t affect them, and there is no need to visually display them. It effectively speeds up the execution phase multiple times.

Extra layer of uncertainty

Uncertainty is what keeps games exciting and less monotonous. Usually, turn-based games supplement it with a dose of randomness, and/or some variants of fog of war (for example, in card games, you don’t know what your opponents have in their hands). Simultaneous turns can also be treated as a fog of war variant, where you’re unsure what your opponents will do. For example, if your opponent decides to retreat his units, all attacks targeting their positions will miss, because they’ll no longer be there once your attacks are fully executed.

Strategic depth

As opposed to reaction-based games, in games with simultaneous planning, you have to outsmart opponents by predicting their actions. It may become even more difficult if our opponent also tries to predict ours – it creates a chess-like mind game, where players try to predict what predictions opponents could predict.

Drawbacks

Lack of clarity

It’s an issue that may affect non-auto-battler games with simultaneous planning. In some games (such as “Infinity Wars: Animated Trading Card Game”), players can queue dozens of actions during the planning phase, such as moving units from one zone to another, activating units’ effects, or playing cards. Since some of these actions can have multiple targets or no targets at all, it may be difficult to visualize all the planned actions, especially considering that the order of actions can matter.

Players who have to make dozens of orders during a single turn may, at some point, lose track of what exactly they commanded and in what order.

This issue doesn’t affect auto-battler games, because in such games, usually only the final positioning matters, meaning the initial state and command order are irrelevant.

Countless conflicts and paradoxes

This issue affects the game if developers want to design actions to be truly simultaneous, allowing multiple actions to execute at the same time. But the outcome of such action may be unclear.

Imagine that one player wants to transform a unit into a frog, while another player wants to transform it into a dragon. What exactly should happen if both actions are meant to execute simultaneously? Should the unit transform into some sort of a dragon-frog hybrid? Should the actions cancel each other out? Or perhaps the unit should die in a failed transformation?

This issue can affect many kinds of mechanics, such as spawning a unit at the selected spot, moving a unit, changing ownership of a unit, assigning immunity to it, setting its attributes, and so on. The more mechanics are added to the game, the more conflicts appear.

An easy solution to this problem is to resolve actions in a sequence. As a result, the game will lose some of its simultaneous charm, but will become much more intuitive. This solution is also used in regular turn-based games, where multiple effects can trigger at once (e.g., multiple units doing something at the end of the turn). The order of the sequence may depend on the game’s rules. Some popular approaches:

• Triggering and targeting depend on positioning (such as targeting cells from left to right, then from top to bottom; example game: “Faeria”).
• Each type of effect has a different priority (such as healing effects resolving before taking damage from poisons; example game: “Phobies”).
• The oldest entity triggers first (easy to implement; example game: “Hearthstone”).
• The player with initiative has priority (which may add some strategic depth, but also create a problem similar to the first player’s advantage, with a difference that initiative can be rotated between players at the end of each turn; example game: “Infinity Wars: Animated Trading Card Game”).

An alternative solution for this problem is to restrict the design space only to mechanics that won’t cause any non-intuitive outcomes.