Pros
Work life balance depending on what team you are on. Free food, snacks, good benefits A very few smart people worth working with. Friendly people.
Cons
I was an engineer at DeNA, so I will be speaking from an engineer's perspective. This is the place where you will see one of the worst engineering practices being done. If that's your thing, by all means, join this place. Most of the engineering managers are just a bunch of deadweight loss that don't really add value to the company. Only a few are intelligent and know what they are doing. There is currently no VP of engineering and CTO. This is a HUGE red flag for any engineer thinking of joining this company. DeNA does not care about the technology/practices used to build its games. People are getting laid off/fired left and right, but upper management will tell everyone else that those people voluntarily quit the company. So much for transparency.