Humans have advanced enough that they are capable of simulating, entire solar systems that have sapiens life. Earth was destroyed not long after the singularity, because of some experiment that goes wrong in a new scientific field. Two centuries later, whatever a new scientific discovery happens, they begin their experiments in a simulated reality before they do it in ours. The problem is the total disregards of the sapiens life in the simulations by our society they are not considered people (because they are fake, created by humans) with is ironic by a society that has the technology to upload minds to a computer and laws regarding the equality between a.i. and humans.
A certain enterprise simulates, a world loosely based on fantasy worlds, with creatures more dangerous than anything, including something like the dinosaurs. The world has several "species" (more like Neandertals and our other ancestors) of sapients. Each species has a specific group of modifications (that are the prototypes without the limitations that are dictated by the law, the modifications will be available in future decades) that give them the abilities necessary (barely?) to survive their environment.
Is regarding, the technological level that the sapients will have, I don't know how to make plausible explanations of why they are behind even the industrial revolution, of course, some extinct sapients have reached nuclear energy but destroyed themselves blowing each other. I came up with two that combined maybe can achieve what I want. The first is a protocol in the simulation that slows down advancements regarding energy technologies and the second is that the planet is very harsh, even if the sapients survive the majority of their predators and even hunt them too, there are some that are impossible (Megalodon but in the ground?).
PS - I don't write English very well, please have patience with me.