Zynga is the king of beating a dead horse and then blaming the stick for not going fast enough. There is precisely zero attention paid to all of the terrible choices made when designing a game, so they just keep getting made again. Zynga is fantastic at getting a short-term return, but has proven consistently blind to the long-term effects of that work.
As for the day to day, there is so much time wasted scrambling to get things done that they always have to be done at least twice, because something will inevitably get missed and need to be fixed. Deadlines are short and work volume is completely unreasonable, so the overtime is absolutely constant. This isn't the worst thing if you are hourly and don't have anything better to do, but if you're salaried, or have a family, then it is just constant stress as you try to dig yourself out from under the pile of work that you're doing for not nearly enough money.
Basically, if you want to see the corpse of the company that made you hate facebook games as it shambles through a hollow parody of game development never quite realizing that it died five years ago, then give Zynga a try.
Easy experience for a real job, a primer on what not to do as a business
Everything to do with game development