To make the plot more interesting, the game settings stated that in some corners of this world, not only were there animals and plants that didn't mutate, but there were also animals and plants that mutated in a direction beneficial for them!
This was also in line with how everything developed. No matter how terrifying the virus was, it was impossible for it to spread to every place evenly and cause similar changes to every mutated animal and plant.
However, if it mutated in a good direction, the speed it mutated would be much slower, and the number would be pitifully small. It would be very difficult for humans to discover them, and even if they did, they wouldn't dare to use them so easily.
Even if the humans were familiar with them, everyone was busy running and hiding once the apocalypse had arrived. Who would have thought that they would remain useful?
