According to ESRB, this game contains: Fantasy Violence
Parents have nothing to worry about as far as subject matter is concerned. Parts of the game must be played outside though, which might not go over well during the cold weather seasons.
Casual gamers might be annoyed by the fact that Boktai is not a pick-up-and-play title, and makes specific demands on the player based on the location and time of day.
Deaf and Hard of Hearing gamers can enjoy dialog boxes, but will miss out on certain audio cues during boss battles that, while not essential, certainly make combat easier.