According to ESRB, this game contains: Blood, Violence
Parents may or may not want their kids playing Castlevania: Lament of Innocence. Although it is heavily stylized, it is also incredibly bloody though it should be noted that none of the graphic violence is directed towards human beings.
Fans of the Castlevania series might like Lament because of its return to classic gameplay concepts, yet those looking for any substantial innovation might be disappointed.
People who enjoy exploration games such as Zelda will probably dislike Lament. Its exploration elements are rather tedious since their involve lots of silly backtracking, yet finding the many secret areas the game has to offer can be engaging.
Fans of fast-paced action games will probably like Lament. Its combat system is very solid, and its brawls can become quite interesting although I can't imagine recommending it over a truly innovative action game like Viewtiful Joe.
Fans of Dracula or vampires in general might get a kick out of Lament. In terms of gameplay, it's much better than other recent vampire games such as Legacy of Kain 2: Defiance.
Deaf and Hard of Hearing players probably won't have much of a problem with Lament. It's cut-scenes have optional sub-titles, yet there are occasional moments during gameplay where, because of the limited camera, hearing enemies approach from off-screen becomes valuable though by no means absolutely necessary.