Blood: The only enemies in this game are the automated gun turrets. They are programmed to shoot you on site. So when and if they hit you, the main character's blood will splatter onto walls. However, since you see from the main character's eyes (first person), there is no visible blood splatter, just the after effect on walls. The blood effects are similar to Half-life 2 but not as extreme. There is no option to turn blood off in this game.

Mild Violence: The game starts out with the main character waking up in an unknown test facility. You are soon introduced to a disembodied voice of a female computer, who will put you through 19 tests involving a gun that shoots portals. The female computer voice is your only "companion" in the game. As you take the tests, the female computer voice says very discouraging almost inadvertantly sarcastic things that sound a bit like, do not at any point touch the output of the portal gun, as it may kill you, or the radiation in this room is known to cause the loss of teeth, or if you fail this test, an unsatisfactory remark will be put on your permanent record, followed by your death. After almost every remark, she will then use the same tone of voice to tell you she was just joking, and you weren't in any real danger (yeah, right). It's all disturbingly amusing, funny and sarcastic. You soon find out that you're to be terminated after the testing, now to escape....

Closing comment: This is one of the most refreshingly new and interesting games to come out for a long time, and is well worth playing. There is no language, your only enemies are robots (who are far and few between), and the blood is pretty mild. Also, it is difficult, but instead of letting your 10 year old play some violent fighting game, let him use his brain (as the puzzles make you). I recommend this game for ages 10+.