It's not that unusual, my wife's at a AAA Japanese owned company and they do fat bonuses for everyone if a game does well (which isn't a pay raise, but I get the desire not to make it permanent given the next game could flop). That includes people who aren't even on the game, although I imagine it's more if it's your game.

But Japanese do it different from the US and people are expected to stay as long as they can, which is different from US job market. I imagine Korean and other non-US companies have pretty similar setups. Hell, even the US used to be like this before wealth inequality got so bad.