I know how to lower sea levels and done it before with Earth, but the landmasses are still split apart as they are today with some drained water levels.
The problem is that I want to re-create exactly how the landmasses were like by having them joined as they were 20,000 years ago during the Ice Age period. Even if you drain some of Earth's oceans, you can still see the land as it looks today, that's the problem.
A prehistoric Earth during the Ice Age time of 20,000 years ago would not have the ground erosion that would have split some landmasses into separate islands like England, Ireland, Indonesia, New Guinea and Australia. Everything would be perfectly joined as a single solid landmass.
That is the reason why I ask for the need for developers to add a prehistoric Earth from 20,000 years ago into the list of "planets" in Universe Sandbox 2.