Q to spawn green particles, E to spawn Red particles. Red particles are attracted to green ones at a long distance, but repulsed at a close distance. Red ones are attracted to red ones, green to green, and green to red. I'd love it if someone remixed it and made it more complex! Warning: Can get very laggy if you spawn too many particles. The lag goes up exponentially.
While I was making the game in the pegma game jam, I discovered a way to make a particle simulation (Which I've wanted to make forever) so I took a small break and made it.