Zynga seems to be failing now mainly due to saturation point.
It relies heavily on the number of facebook users, especially new users.
The mechanics of facebook games are all every similar. It relies on spamming (your friends) to get anything or spend an obscene amount of money to get similar result.
IMO, their facebook casual games are not even in the same vein as the console casual games. Facebook games relies heavily on spamming to get bored people to try their games.
Meanwhile, console games are usually simple non-violence games and great for pick-up-and-play in short bursts. You play when you want and how you want. No spamming your friends for action points to give you a few extra clicks.







