Ah, Infamous 2. It's hard to pin a straight age rating on a game based so much on choice. I'll start with what it is. In the opening of the first game, Cole MacGrath was an ordinary guy, going as far as calling himself "the guy nobody notices". He delivered packages in the town Empire City. But one package exploded, ravaging his hometown and granting him strange, electrokinetic powers. One thing lead to another, and a giant being of lava attacks Empire City. Infamous 2 opens with him in Empire City's docks, getting ready to leave. A brief tutorial fight with the lava giant (known only as "The Beast") leaves the beast slightly wounded and enraged, and Cole's powers drained. He, his friend Zeke, and a special agent named Kuo leave for a Louisiana town named New Marais, to find the scientist who can amplify Cole's powers. The game then revolves on him amping up his abilities to defeat The Beast once and for all. Along the way, he can help the citizens of New Marais....or kill them. Every person you come across is attackable. Defeating enemies will grant Good Karma, while slaughtering innocents gives (obviously) Evil Karma. Cole's appearance will change depending on which patch is chosen. Good Karma will give his powers an electric blue coloring, while Evil colors them with a redish-orange hue. Karma will also affect the plot, and whether or not Cole obtains additional Cryokinetic or Pyrokinetic powers later on (technically, choosing one powerset grants Good or Evil Karma, so it depends on player choice. Advise your young heroes to side with Kuo, if they want Heroic Karma and Ice powers, and Nix, if they want Evil Karma and Fire ones).
Combat is a blast (literally)! You choose between various Lightning Bolts, Electric Blasts, Lightning Grenades and Rockets (made of electricity, not metal), and devastating Ionic powers to use in combat. Aiming is relatively easy, and Melee combat even easier (just tap square). In Melee (or close quarters, for the less digitally inclined), Cole wields the might Amp, an oversize tuning fork capable of channeling his electric powers in satisfying combos and finisher moves. Cole's foes (that I've encountered so far, haven't finished it yet, might edit when I do) include masked soldiers, hazmat suit-wearing supercommandos (with Ice powers), and Lovecraftian monsters (think Cthulu, and you're on the right track. They have rats with mouths that open into three parts, giant armadillo type creatures with clawed tongues, and a godzilla-like mutant with glowing pink eyes all over it's body). Minor blood is shown when Cole is shot, some splatters on the edge of the screen depending on health level, and occasionally enemies bleed when struck with the Amp. One combo involves the Amp being rammed through a foe's neck, although surprisingly, no blood is shown. Skeletons are visible when foes are electrocuted, and creative players can "torture" enemies by electrocuting water as they stand in it (a guaranteed kill). Cars can also be Telekinetically thrown at enemies and citizens alike, and for every mugging or abduction in progress stopped, players can also murder innocents, kill street performers, and rack up a ton of property damage (which doesn't give any Karma, good or bad).
Phew, okay, combat down, now on any disturbing imagery. Cutscenes are comicbook-esque, but feature large explosions, minor blood, a first person view of masked vigilantes standing over a downed citizen, and (memorably) a man transforming back from being a mutant. The right side of his face is covered in eyes, and his left cheek is a part of a jaw covered in fangs. He is also naked, although nothing is shown. A scene of a makeshift hospital full of terminal patients could be disturbing for some younger viewers. The Beast may seem scary, and one ending results in Cole electrocuting one of his friends to death.
A "red light district" is in the game, some neon signs advertise "nude girls", and others depict scantily clad female silhouettes. No nudity is shown in game. Some revealing outfits are shown (worn by Nix and, later on in the game, Kuo).
In short, Cole MacGrath can be a hero, but Superman he ain't! He can be played as either an anti-hero (think, modern incarnation of Batman) or a sadistic thug. Remember that it's a good alternative for kids begging for Grand Theft Auto, even if it isn't the lightest-hearted of games.