According to ESRB, this game contains: Blood and Gore, Intense Violence, Language, Sexual Themes
Parents will want to pay close heed to the M rating. Digital Devil Saga isn't a game for youngsters. There's the whole cannibalism element, lots of blood, some swearing, and more—plus, the story is pretty complex as well. It's really something more for adults/mature teens than the younger gamer crowd.
Hardcore RPG fans have found a game worthy of their love. This is a deep, complex, and involving RPG that breaks from the mold of the genre in ways too numerous to mention. They don't make many games like this one, and I've no doubt that in a few years people will look back at this as one of the defining role-playing games of this generation.
Casual gamers will no doubt be put off by the high random encounter rate, learning curve, and abundance of dungeon crawling. Those who stick with it will be rewarded with an engaging game experience—but make no mistake, this is a game that tends to appeal to a mostly niche audience. That being said, this is the most accessible MegaTen game I've played and makes a fine starting point for anyone curious about this franchise.
Deaf and Hard of Hearing gamers will miss out on the great music and the mostly excellent voice acting, but the game is still accessible thanks to full subtitles.