The Bible tells us to think about what is noble and what is pure. It also tells us that whatever we do, we do for the glory of god. If a M-Rated game follows these guidelines, then I don't see how it can be a problem. I know there are M-Rated games that are very noble and pure in their thought, but have objectionable content. Let's take for example a game of mine that I find to be very great: Metal Gear Solid 4: Guns of the Patriots. It has an M Rating for the following reasons: Blood, Crude Humor, Strong Language, Suggestive Themes, Violence. So let me take them into consideration.
-Violence: Sure the game is violent, but you are encouraged in the game not to kill any one. You collect Drebin points throughout the entire game, and the lower your kill count, the more points you get. You can just use your tranquilizers on people and save the other guns for the robots. Nothing wrong with destroying evil things that man creates.
-Crude Humor: I can't remember much off the top of my head, but I don't remember anything too horrible in the game. Can someone back me up? Having said that, Crude Humor isn't my cup of tea, but I can manage with little amounts.
-Strong Language: This I find inexcusable. The one thing I did not care for in the game at all. I think this isn't even that necessary.
-Suggestive Themes: All of the female boss characters wall towards you in provocative ways. They also wear skin tights suits. Doesn't sound like something pleasant, but if you approach the females, your pretty much dead. It's very hard to fight them close range, and you'll lose nearly all your health. If they would have buttoned up Naomi's shirt, this would have not even been the smallest of problems with me.
-Blood: See violence section. This can be nearly skipped except for in cutscenes.
-Themes of the game: Self Sacrifice for others, learning there is always value in life, destruction of war on the world, and how the world may turn war into just another economy. This game has enormous value for me. Snake is a true hero, and I've felt for him in every Metal Gear game I have ever played.
In an M-Game or other rated one doesn't encompass good thoughts, stay away from it. Examples include Grand Theft Auto, Max Payne, Saint's Row and Leisure Suit Larry. There are also games where you have to be cautious about your decisions, such as Fallout 3 and Elder Scrolls IV: Oblivion.
I also don't really care for games where the violence is real gory where all they did was add buckets of blood for odd reasons. For example, I think Gears of War could have gone a tad easy with the chainsaws. I can play games like Silent Hill where it's more dark and blood is used to scare you than to just make a gory mess. I also think games like Dead Space aren't that bad in that when you shoot at the arms, the only thing that happens is that the arm falls off. Violence isn't bad unless it is glorified in a senseless way.
As for online shooter games, I don't have that many problems with them. Most of the time, you shoot someone, and they disappear, and respawn back into the field. Sounds kinda like, well, Football to me! I don't care for elements in the games where you can have cruel violence such as killzone 2. When you die, you are only mortally wounded, and someone can take a shotgun or machine gun and shoot you even more. I find this rather disturbing. I'd rather play one like Uncharted, where they just die, disappear, and respawn after you play. If you play these games, might I suggest a christian clan?
For closing remarks, I've said what I believe. You don't have to think like this, but take whatever you do up with God first. I prayed with him week after week if it's okay to play shooter games, and he keeps telling me not all of the shooter games out there are bad. In fact, he wants me to join a clan to be a witness for him in the gaming field.
