Every creature in the dish has a real neural-network brain. The ones that eat survive and split; their children inherit the brain with small mutations. The rest die. Buys drop food. Sells bring droughts and predators.
Click any creature to open its brain.
Measured from every creature that has ever died in the dish, grouped by generation. Nobody tunes these numbers; they come out of the brains that survived.
When a family takes over, it gets a name and an entry, written from its measured behaviour. When the last one dies, the entry stays.
8 senses go in: food on the left, food on the right, danger on each side, how close the wall is, which side it's on, its own energy. 6 hidden neurons. 2 outputs: turn and speed. That's the whole creature. No rules about hunting or fleeing are written anywhere.
With enough energy a creature splits. The child gets a copy of the brain, and about one in ten connections changes slightly. Most changes do nothing or make things worse. Once in a while one helps, and that family takes over the dish.
The world reads the $ORIGIN chart every 3 seconds. A buy drops a cluster of food somewhere in the dish. A sell dries the food up for a while and releases predators. Busy trading feeds a boom; selling pressure decides who survives it.
It doesn't reset when you close the tab. Everyone sees the same dish, the same families and the same history.