~15 hours in now, I didn't have fun and I regret my purchase.
I won on the highest difficulty on my first playthrough. This is the 1st time I've ever done that in a Civ game (played them all since Civ II). I've only won one maybe 2 games of Civ IV on the highest difficulty, in hundreds of hours.
Broken aspects of the game include land improvements that provide health, trade routes which can tripple the production of cities or espionage which allows you to easily steal cities without even declaring war. The aliens cripple the AI factions while they barely hurt me, except for the siege worm, which I just avoid for a while. Other than orbitals, everyting in the game is a reskinned Civ V feature. The factions are soulness, the leaders are all the same, diplomacy seems even worse than Civ V. Playing large maps is a chore, everything needs micromanagement. The UI lacks Civ V basic features. I could go on..
I may give this another go in 2 years but I'm afraid it won't have the stellar sales of Civ V so there won't be as many DLCs or expansions.