I highly suggest that you block off rated "M" games for kids,like if their account is under 17, then just let the screen say, "Sorry, but you are not eligible to play this game" Just a thought
Dark Cut has a warning, if I remember correctly, and Toybox is kinda freaky as well. Most gamemakers seem to want to be on the safe site, and make a warning in the beginning of the game, though. Besides, if you conclude you will be unable to handle the game in its first minutes, just close it down. The first minutes, or even the menu can be enough to tell the nature of the game.
