Neanderthal is heavily influenced by Julian Jaynes’ Bicameralism, which is… controversial science.

en.wikipedia.org – Bicameralism (psychology) – Wikipedia

From a game standpoint, I recommend starting with Greenland. It’s more straightforward, and you’ll learn some basic mechanisms that are transferable to Neanderthal, which takes the basic Greenland mechanisms and adds the “brain game” on top of it.

I confess I think of the two, Greenland is the better game 🙂 It’s still capricious, brutal and unforgiving though. It’s an Eklund game after all.