Of course it's possible. Overrated and underrated don't necessarily need to refer to the entire of the gaming community. By FF fanboys, I'd probably say that the game is overrated, but I'd also say that some people are unfairly critical of what is a good game. It's hardly the pinnacle of human achievement. After all, such judgements are entirely subjective anyway and it depends on whether you like the game or not.

I'd say the game is more overrated than underrated, but it's certainly possible to be both provided you mean by two different groups of people. Or people with multiple personalities.