Design Statement
The first word I thought of when I heard the theme track was "journey." Its slow climb, emotional peak, and sudden stop reminded me of Voyager 1: a machine that travelled farther and farther from home, then turned around for one last photograph.

I built the game around being the spacecraft itself. Looking and turning are separate actions: the camera has limits, while thrusters rotate the whole body. Four senses—camera, infrared, plasma waves, and ultraviolet—let players discover different aspects of the same world. As the years pass, power decreases and those senses gradually disappear.

The journey follows Voyager 1's encounters with Jupiter and Saturn, ending with the 1990 family portrait. Music layers respond to discoveries and moments of departure, building toward Earth as a tiny point of light. Switching off the camera makes the loss something the player does, rather than merely watches. The ending pairs the player's photographs with real Voyager images, connecting a personal journey to the historical one.

Game Instructions (launch steps, controls, and gameplay overview)
Download the Windows or macOS build from the project page and extract the ZIP. On Windows, keep the .exe and .pck together and run 6-Billion-Kilometers.exe. On macOS, open the included .app. The game does not require Godot to be installed.

Keyboard and mouse are required. Move the mouse to look; hold right mouse or Shift while moving to turn the spacecraft. Q/E rolls left/right. Keys 1–4 switch the four senses. Hold left mouse or Space on a target to record it. Space/Enter continues dialogue. Esc opens instructions, settings, language selection, and the gallery; F11 toggles fullscreen. Controls are introduced gradually in the opening tutorial.

Follow Earth’s radio instructions, observe and record discoveries, and send your pictures home through the Jupiter and Saturn encounters and the long drift. A playthrough takes about 30 minutes. English and Simplified Chinese are supported; change language in the Esc menu.

Gameplay walkthrough video
https://youtu.be/2aPNxQDShmI

Trailer / Other Additional Video Material (Optional)
https://youtu.be/uWL-4nsl-eM

Did your project use any AI tools or assets? If yes, please specify.
Yes. The six in-game music tracks and the trailer music were generated with Suno, then arranged and integrated into the game.