Great game. Basically the same as the first as far as violence, blood, and gore. There is killing of aliens, and when they die, green, or purple blood spurts out. There is also a parasitic, zombie-like form called the Flood that you fight. Those are really gory. Mild to moderate language sprinkled throughout. May be frightening to children under 10.
Players use automatic rifles, high caliber pistols, semi-auto rifles, SMGs, plasma-based guns, grenades, turrets, rockets, and energy swords.
PS: the "What Parents need to know" thing at the top says "torture". I played the whole game several times, last time just a month or two ago, and I didnt see any torture.
Verdict: good for 14 and up. maybe for 11 and up. Definitely not for kids under 11.