Game Design: 1. Initial Proposal & Nondigital Prototype

Introduction

In February 2023, We, the Aphelion Defense Studio, started our first game project called Aphelion Defense under the instruction of the CS 5152 Advanced Game Design course from Walker White at Cornell University.

Our interest lay in a space-themed multiplayer RTS game. In the first proposal, we propose a game in which the player must focus on managing their resources, which includes energy and units, to eliminate enemy players from the solar system. Thematically, the player is at war with space-faring enemy civilizations that wish to acquire more territory and conquer the player’s civilization. The multiplayer aspect of the game will require the player to strategize quickly while considering the potential actions of opposing players with the same abilities.

Core Mechanism

We developed the core mechanism by holding regular discussion sessions where we think the dynamic movement of planets could be a point allowing a lot of interesting gameplay to happen. We also introduced the concept of “sunlight” as it is dynamically changing based on the position of the planet, and “move distance“ as the relative distance between each planet in the universe is always changing. Keeping these in mind, we proposed our very initial game mechanism:

The player planet passively generates a resource “sunlight” every unit of time, and the amount of “sunlight” gained is inversely related to its current distance to the sun. The closer the planet is to the sun, the more “sunlight” is produced. The planet also passively generates a resource, “troops” that are used to claim other planets and defend player planets. To overcome the challenges posed by the enemy and the scarcity of resources, the player needs to employ the mechanic of attack by taking the action of directing troops to attack enemies’ planets. There are 2 types of troops high damage but can only travel short distances and low damage but can travel long distances. For an interaction of battle to actually happen, the player must wait until the enemy planet is in “range”, i.e. the planets are close enough in orbit so that the chosen troop type can reach the enemy planet. If the planets are not close enough for the selected troops to reach the destination, the mechanics will fail and nothing will happen. If this succeeds, troops then leave the player planet, decreasing the number of stationed troops and sending troops to the enemy planet. Once the troops reach the planet, a battle will occur. The battle's outcome is determined by the number and type of player troops sent, and the number and type of enemy troops stationed at the desired planet. Pathfinding and battles are done automatically.

Non-Digital Prototype

To help us better understand the Gameplay we are developing, we initialized a non-digital prototype, which allows us to make prototypes rapidly on our gameplay system and allow more discussion to happen when we play it.

Our game board features four different orbits with a varying number of orbital positions shown by the circled numbers. The number represents how much sunlight the planet will gain when at that position in its orbit. The yellow lines between the orbital positions represent where units are able to move, so if two planets are at orbital positions connected by a yellow line, units can move between those planets. Finally, we have a simplified version of the rules to remind players of their available options in a turn.

We have six different pieces for our game. Three of the pieces are colored circles representing player-controlled planets (green), AI/player 2-controlled planets (red), and neutral planets (blue). We have rectangles with an icon of a sun on them to represent one sunlight and orange rectangles to represent units. Finally, we have orange “houses” to represent the different levels of planets as they are upgraded.

Nondigital Prototype PlayRule

Our non-digital prototype is a turn-based board game with two players. Each player starts with one planet they control and their goal is to conquer the rest of the planets in the solar system while the other player works against them. To do this, they must have at least one unit on each of the planets in the solar system.

The game starts with the pre-turn phase, where each planet moves forward one step in their orbit and resources are gained according to the following rules:

Players acquire sunlight from each planet corresponding to the number underlying the spot the planet is in in its orbit, which is proportional to the planet’s distance to the sun.
Captured planets acquire x units, where x is the level of the planet (starting at level 1).

The next two phases require player actions where one player goes before the other. To make it fair, player turn order is reversed every turn, with the green player going first on turn 1.

The next phase is the spending phase, where players can spend their accumulated sunlight on the following actions:

Upgrade a planet. This costs x sunlight to upgrade a planet to level x from level (x-1).
Move planets additional steps, where one sunlight moves a specified planet one step.

The game then moves on to the action phase, where players can move units and attack according to the following rules:

Each unit can only move between planets once per turn.
Units can only move across the yellow “bridges,” which only exist between orbit locations that are close enough together.
A player must keep one unit stationed on a planet to retain ownership of that planet.
If a player sends units to an opposing planet, units cancel each other out until only one player’s units remain. The winner gains ownership of the planet.
Buildings (upgrades) remain intact if “combat” occurs or if a planet becomes neutral.

When one player gains control over all of the planets in the solar system, the game is over and that player wins.

Playtesting Results

We held a non-digital prototyping playtesting session in the class where we got many useful insights from the discussions that happened there. Here we summarized:

Game Speed: Avoid slow gameplay and downtime by having players make decisions at almost all stages of the game.

AI: Due to the complexity of the game, creating an AI is difficult, so they have decided to pivot towards networked multiplayer.

Planet Distance From Sun and Orbit: Create a benefit for being far away from the sun or a disadvantage to being close, and include more elliptical orbits for more interesting gameplay.

Sunlight and Planet Movement: Find other uses for sunlight or make the two options more equal in value. Make planet movement a more viable option to introduce more strategy.

Units: Balance the relationship between upgrades, planet distance, and unit generation for a more balanced economic system that still allows players to take ownership. Need to balance the economy in the digital prototype.