First of all, I have only played the demo, but it also contains the only content parents should be aware of. First of all, this was my first Pikmin game, so I cannot compare it to previous titles, that being said, I knew somewhat about the series before playing (Pikmin are plant aliens, Onions have Pikmin in them, Bulborbs are baddies, etcetera). The graphics were AMAZING. These graphics make Splatoon look like Super Mario 64! That is right. The fruit looked perfectly textured, the environments were heavily detailed, and although the characters look cartoon-like, that is too be expected from a Nintendo game (besides some titles like Twilight Princess) and the colors are still realistic enough. One of my only problems about this is that the days are too short. I would get real innovated in a task, then I needed to stop and try and get all my Pikmin that are alone before they got massacred, then fly back to continue the next day. Also, the demo is too short, but, well, it IS a demo after all. And I get that the full game has 100 Days while the demo only has 6, the full game could most likely be completed in only a day and an hour (if the person LITERALLY does nothing else that day and hour). Now, onto content!
Violence: Cartoon-like and mild. In this strategy game you use wee extraterrestrial animals (Pikmin) to perform tasks around a fantastical planet. Tasks generally involve removing obstacles, bridging gaps, or fetching fruit for the your space shuttle. Players encounter bug aliens that attack (e.g., spew flames, electrocute, bite/stomp/eat the players' Pikmin). Pikmin attack monsters by slamming or latching on and whacking them with their buds (flower antenna). From what CSM said, boss fights in the full game require prolonged battles with large monsters.