According to the ESRB, this game contains: Comic Mischief, Mild Language, Mild Violence, Suggestive Themes
Parents should be aware of the game's increased difficulty and the frustration that comes with it, but otherwise this is generally safe stuff if you don't have an aversion to guns. There is no questionable language I can recall (there might have been a 'damn' or something in there), no real gore, nor any sexual situations.
Platformer fans will get something that's pretty solid, but not very enjoyable. The production levels are just fine, but the fun factor is sapped and a lot of the missions are repetitive. There are better choices if you need a platforming fix.
Returning Jak & Daxter-ers may not like what they get. With a much bigger emphasis on guns and a "grittier" hero, you might think you're playing a weak version of Ratchet & Clank with the humor stripped out of it. The first game was much better.
Deaf and Hard of Hearing gamers will be mostly okay, but be aware that there is no text for many of Daxter's quips, nor is there any for when the game gives you new instructions during a mission. Also, there is one puzzle based on musical notes with no visual way of solving it. Dig up an FAQ for that one.