According to the ESRB, this game contains: Mild Fantasy Violence, Sexual Themes, Use of Drugs
Parents should feel fairly safe with Riviera, although it is aimed at teens or above. The violence isn't anything to get excited about. It's mostly cartoon-style swords and monsters without any gore. I don't ever recall seeing drugs of any sort being used, although it's mentioned on the back of the box, but there are indeed some sexual themes. The main character engages in a few double entendres at times. There are at least two bathing scenes featuring multiple females (nothing explicit is shown), and there are a few conversations that may be a wee bit on the risqué side. Personally, I found it all to be in good fun, but be aware that this content is in the game.
RPG fans should definitely pick the game up. It may not be pushing the edge technically, but games featuring this much interaction between the characters on this sort of level are very few and far between, and in my opinion it was very well done. The game is also worth checking out for the simple fact that it takes a very fresh approach to both exploration and item implementation. People interested in exploring other schools of RPG thought will find a lot to chew on here.
Deaf and Hard of Hearing gamers will have no problems. All dialogue in the game is presented through text, and there are no significant auditory cues. In fact, I played this game entirely with the sound off and never had any issues. Thumbs up.