I got it, and here's my opinions on the 5 stages:

Cell - great fun despite its simplicity.

Creature - I had imagined that it would feature wandering animals... instead of aninmals staying in their nests!

Tribe - Tried to act like an RTS but it is not, why can't they just stick to a RTS interface???

Civilisation - Short and simple, spam vehicles and bomb the others to oblivion. Still, it has a certain charm to it, unlike the Tribal phase.

Space - VERY VERY VERY fun! and I just started it (Hunting Pikachus right now )