A 3D action game made solo in ~4 days for the GMTK 2025 Game Jam.
Play it here: https://gilbz.itch.io/bloodstream
You play as a red blood cell piloting a boat through the human circulatory system. Navigate between organs — lungs, heart, liver, stomach — picking up and delivering oxygen and CO2 while fighting off viruses. The longer you survive, the harder it gets.
Built with Godot 4.4 (GDScript).
- Custom buoyancy physics — RigidBody3D with probe-based flotation, water drag, and passive river current forces
- Dijkstra's pathfinding — used to calculate shortest routes between organs and guide the player with a directional arrow
- Enemy AI state machine — viruses use NavigationAgent3D with wander, chase, and attack states triggered by proximity
- 8-stage difficulty system — enemy count scales from 0 to 10 over ~12 minutes, with stage transitions announced in the HUD
- Spline-based river generation — organs connected by Path3D-driven multimesh blood vessel pathways
- Delivery objective system — tracks oxygen/CO2 deliveries with STARTED → RETRIEVED → DELIVERED state transitions
- Dynamic spatial audio — 3D-positioned sound effects with pitch randomization and pooling
- Full HUD — health/gas bars, elapsed timer, active mission display, difficulty indicator, and game over screen
- https://opengameart.org/content/seamless-water-tiles
- https://opengameart.org/content/animated-water-texture-128px
- https://github.com/immacu-late-lift-studio/Godot-Ocean-Shader/blob/main/ocean_surface/clear%2Bsea%2Bwater-2048x2048.png
- https://opengameart.org/content/700-noise-textures
- https://www.zapsplat.com/
- https://www.kenney.nl/assets/impact-sounds
- https://freesound.org/people/qubodup/sounds/442773/
- https://poly.pizza/m/59muuwqSsq — carrot model by Kenney (edited)
- https://freesound.org/people/modusmogulus/sounds/792520/
- https://freesound.org/s/133901/
- https://opengameart.org/content/crosshair-pack-200×
Shader reference: https://godotshaders.com/shader/psx-style-water-surface-pixelation-waves-scrolling-textures/
Attribution:
- Sound: Motorboat on the Mekong River, Ben Tre, engine noise as boat runs up river | Produced by Martinimenisc us | CC0 1.0 Universal License
- Sound: Motorboat on the Mekong River, Ben Tre, engine runs, slows to almost conking out, starts again and accellerates | Produced by Martinimenisc us | CC0 1.0 Universal License
- Sound: Lava loop.wav by Audionautics -- https://freesound.org/s/133901/ -- License: Attribution 3.0