Pros
You get to work with very intelligent, ambitious and driven colleagues (and get to build a network with these folks). You will most likely have the opportunity to learn a lot in your field. The perks (free food, snacks, happy hours etc...) were not bad either. The best aspect for working for Zynga was the career opportunities it opened up. However, I feel this is diminishing as the company continues to decline.
Cons
The company is very disorganized and so political that the environment has often been described as a modern day "Game of Thrones." Incentives across cross-functional teams are horribly misaligned, and lead to a lot of internal confrontation. The environment is currently very very unstable with high levels of attrition across the entire organization. Most employees have been at the company for less than a year since experienced employees often leave for greener pastures. To make things worse, it has become difficult to attract domain experts as they have more attractive options elsewhere. I should emphasize there is a lot of infighting between teams, which is extremely counter-productive and leads to lots of daily stress You will run into employees with absurdly high-egos, the company does not believe in the "no a**hole" rule. Given the disorganized structure, political infighting across teams, and high levels of attrition...the company is the pinnacle of the "everyone for themselves" organization...it truly is a free for all. Do not look for mentorship or expect to see great leadership here, you will find neither. Lastly, there is zero work-life balance - you will be overworked (churn and burn).