Pros
Office location is good. If you are lucky enough to have a good manager, then you pretty much can have flexible working hours. Most people are friendly. Have compensation for house rent if you live near the office. Have compensation for purchasing the latest model of smart phone every year.
Cons
Terrible senior management team, short-sighted macro decision making, randomly cutting out ongoing projects for no reasons. Many people quitting their jobs because of this. Office politics is everywhere. Most engineering teams are technically conservative, insanely obsessed with using PHP to develop everything, not willing to even consider adopting other technologies. Not serious about making good games, the only thing they care about is how to get players to buy more in game items by repeatedly creating in-game events. It is pretty common for most people if they don't get a salary raise for a whole year. Unfair promotion opportunities for foreigners. This is not a good place for non-Japanese employees.