I will say that the game's ending is very drawn out, probably excessively so. From what I can tell, I have one mission left in the Apocalypse folks, one or two in the undead chain and three or four left on the aliens. With the average rate of story creation, I'm looking at over a year of just downing UFOs and waiting as the rest of the planet is pacified.
I think the issue is that early chains made it clear that advancing too many chains too quickly leaves you strained to handle the dozen or more high level missions that spawn each month, but if you are too selective with research, you end up in a scenario where the end game drags on forever.