Okay I know that most people aren't going to read this review because it's coming from a 15-year-old, but if you've read this far keep reading.
I got Modern Warfare 3 (Mw3) for Christmas 2011, and it's the latest Call of Duty game I've had since Call of Duty 2 (cod2), and it was a major step up. Ever since I had played Modern Warfare 2 at a friend's house, I've been wanting to get a new Call of Duty game since. The graphics, the enhanced multi-player, the customization, the perks system, the leaderboards, everything. I kept looking at reviews to try to get my parents to buy me the game, but for two years they stuck to the stubborn response of "It's and M rated game." Finally however, either they approved of my high school grades or felt that I was mature enough, I got the game along with a Playstation 3 (PS3). Immediately I plugged the system in and inserted the disc.
First things first though. When you get the game, and you're not a very experienced Call of Duty or first-person shooter (FPS) gamer, play the single player first, or you'll get crushed online. Even after previous experience with other COD games and after playing though several missions on the single-player campaign, I went through my first online game at a miserable 2 kills and 20 deaths. If your kid goes straight to the multi-player (There will be a message that strongly recommends that you play the single player first) and doesn't have any kind of experience, he'll get destroyed by people who have been playing the series since Call of Duty 4/ Modern Warfare 1, a whole 4 games ago, and will get discouraged.
Okay so onto the part that most parents probably care about most. The reason that the game has an 'M' rating. Well first thing's first, in America, if you're game has blood and mild swearing and is rated 'T', you'll get sued. Also, the ESRB's rating system isn't very specific in my opinion. The 'M' rating has quite a large range, from the 'M' games that couldn't quite make the 'T' rating, to regular 'M' games, to 'M' games that are nearing the Adults Only 'AO' rating (Sony (PS3), Mircrosoft (Xbox360), and Nintendo (Wii) never allow games with an AO rating to be published on their platforms). Modern Warfare 3 tends to be slightly towards the lower side of 'M'. However it still has its reasons.
Your kid is probably getting the game strictly for multi-player (or possibly for Special Operations or 'Spec Ops'), so I'll review that first. The first thing you need to know that this is where the game could pretty much be called a 'T' game. Blood is very minimal, characters in-game don't swear, in fact, all the in-game voices are notifications that help out your team except for the lines said at the beginning and end of each match. This is an improvement from COD World at War (WaW) (the 5th game in the series), because Mw3's beginning and ending lines don't contain swear words and aren't as 'negative'. For instance, a beginning line in WaW in free-for-all (every man for himself) is "Kill all who oppose you" and an ending line for U.S. Marines is "Outstanding Marines! Outfu*****standing!". Mw3 doesn't use these kinds of lines. Instead of blood spraying out of shot opponents, something that looks a lot like money flies out, which I'm not sure what that purpose is for or if it's suggestive of anything. The only problem I have is that the players online aren't the best, epecially when it comes to vocabulary. Many players online swear constantly. If a person you kill has a mic, (you can't hear the other team in team based games), you'll have about a 1-1.5sec space where you can hear their reaction. Usually these contain swear words from either frustration or shock. However you can pull up the leaderboard by pressing 'select' on your controller, and mute those people by selecting their name. This gets read of the swearing problem at once. Another problem with the online is that if your kid doesn't like practicing to get better, he'll drop this game quickly. Many people on this game are pros, and I still usually have more deaths than kills every game. Definitely stay away from the Search and Destroy game mode if you're inexperienced, because the people on that game mode are hardcore players that are extremely good.
Alright onto single player. This is where the game gets its 'M' rating. Also, the more accurate you are with a gun, the more violent it is. I played a mission with a sniper rifle after i had some experience online, and most of my shots were headshots. No matter the gun however, headshots usually result in blood spraying out of the enemy's head, and, if they're close to a wall, splattering against it. Knifing an enemy usually has blood come out of him at a very close perspective, and dead enemies will occasionally have pools of blood coming from them. Players will see many allies die in combat at the hands of Russian and/or terrorist hands, even quite a few main characters die. One scene depicts a family in vacation in London (where you actually control the father holding the camera), where a mother and her daughter are blown up by a truck bomb and the father (you) dies almost instantly from a poisonous gas that's spilled out all over London. The game however gives you a few warnings about this scene and lets you skip it without being punished at all in terms of medals/trophies or anything. All in all, the campaign is where Modern Warfare 3 gets its 'M' rating.
A little side note for Spec. Ops. it's like a cross between multi-player and single player. The missions and modes can be played with one person, two people, or with another online (again beware of swearers). The violence is slightly up from multi-player, but not as much as the campaign.
Overall, people play the game mostly for the multi-player action (and possibly the new 'Survival Mode' in Spec. Ops.). Most people don't play it to kill avatars though, it's for the points and endless competition the game offers. The story-line is fairly immersing (starting off right after Modern Warfare 2 ended), and has tons of replay value. Just know that online players are very tough (they make even the toughest enemies in single player pathetic at times), and the single player is rated 'M' for a reason. I'll say a line that's probably overused by now, but if you're kid is mature enough, this game is worth it. If he/she starts slipping up in things like school however, take it away. I suggest playing it only on weekends (anyways that's when the less experienced people are online anyways), and defiantly not before exams (I never had time anyways). Some say that this game is great for venting out a bad day, but only if you're good at the game, cause being beaten won't help (although I also have a great time played weather being destroyed or not!) Once you've gotten used to the game however, you'll find that Infinity Ward, the maker of the game, added some things that help new players out, such as point streaks that don't reset on death. Thanks for reading!