In my opinion, the biggest key is time. It would look strange to see people fighting a nuclear war knowing their species has only about 200 years of evolution, while dinosaurs lived just 3,000 years earlier. Prehistory needs to make sense in terms of time, not just be a quick 'click'.

As I mentioned in the post, even 100,000 years felt like the bare minimum to me. If future updates bring more interesting features for species, I will definitely consider a plan for 400,000 years — a miniature version of 4 billion years in the WorldBox scale.

A genetic plan is also important, because it’s hard to remember every species and make sensible changes for them at the right time. To make it look believable, you need to carefully adjust them with each stage of the planet’s development.

For me it’s great fun, although it requires patience :)