My first M-rated game was either DOA extreme beach bolley ball or Halo Combat Evolved. One of my friends he brought his Xbox he had both of those games and a few others I don't remember.

My first M-rated game was Persona 3 Portable or was it God of War: Chains of Olympus.

That is a hard question for me to answer.

"NARC" for the Arcade "Coin-Op." It has got to be.

They did not have the rating system till the "Playstation one" I think.
The first Game that I remember having an "M" rating Stamped on it on it was "Conkers Bad Fur Day" for the "N.64".
But
I have played games that were way more graphic than that before the rating system.

I typed up a bunch but everyone has mentioned them I think. So I erased the list and went with the one that I remember shocking me the most.

I have to go with "NARC".
Granted it was not rated. But there was a ton of wild stuff that just seemed over the top with that game. (If they were to re-release it? It would be rated "M" I think.)

The reason it was not rated?
Parents watched their kids in those days. The kids that did not need a chaperone "24-7"? Were safe from all of the wild stuff you hear about on the news today due to the fact that people were very much "tame" in general compared to modern day standards. (If there are any anymore.)

Plus kids sometimes were afraid of getting into trouble in that time.
Some would not dare to upset the parent or guardian.
Besides, Arcade games were a big hustle in those days. The more realistic the graphics or the more adult themed content? Often equated to a game that sucked money from the player instead of presenting a proper challenge. Too high a difficulty or cheap difficulty.
Kids typically skipped those machines. Particularly after seeing a grown-up blow through four quarters in four minutes.
Respect for ones Elders tended to pay off in those days.

Today? Its a Different world. Is it not?
Good question.
Thanks for asking.
Good Luck.

Good Luck To All.
I'm done. Stick a fork in me.
Peace.

jmc1097 : The first "M" rated game I ever played was Jaws.I was renting it for about 3 weeks, this was a couple of years ago, before my family had a computer.That is the only game that I have played that is rated "M"."M" stands for mature, which is only for people 17+ years of age.

The first M rated game I ever played was either Halo 3 or Gears of War. I can remember which one it was because it was at a friends house quite a while ago.

The first M rated video game I ever played was Grand Theft Auto 3. At the time I was 12 and the only reason I was able to play it was the fact that I was over my best friends house and he got the game for his birthday.

I hate them all!
But I have played Call Of Duty:  Black Ops, I went 1 kill, 38 being killed.
I am wonderful.

It's either Call of duty 4 or Doom, I can't remember...

The first M rated game I played was Grand Theft Auto on PlayStation 2.

That would have to be Mortal Kombat . I played it when I was like 12. I was underaged of coaurse just like everyone who played a mature game for the first time.

I've never played any M-rated games before and I probably won't ever play any. For now I am sticking with retro games and hacks of my favorite retro games.

Doom for the SNES. I've been playing M rated games since I was 6. And contrary to popular belief, I grew up just fine. Never was disrespectful to my parents and never went on a shooting rampage.

The first m rated game I played was evil dead: regeneration.

the 1st gta game ever on ps1

A few years ago I managed to get my dad to buy me Halo 3, That was the first full M-rated game I had since I had played a Demo of Force unleashed 2 and had found a flash game of the first episode of Doom, Which two years on I was searching for the full version of it and that's how I found vizzed. I think the most gory game I play was Mortal Kombat 9 at my friends house, he taught me some fatalities so it did get very brutal. 

My first M-Rated game was Conker's Bad Fur Day my uncle gave me with his N64. I seriously loved that game, even if it was a little graphic.

GTA [insert name] ...I used to laugh like crazy while suiciding off of buildings and creating chain reaction car explosions on the highways. A vivid memory I have from GTAA is when I jumped out of a helicopter and died on the spinning Burger Shot sign. I had to turn the volume down at cutscenes so my mother wouldn't hear all of the swearing XD

I believe it was one of the early Call of Duty games. Seeing that my cousins were older, they generally went with the crowd, and bought these games. I think it was World at War. I didn't really get into fps games until my later years up to now. Eventually you get tired of them, and they disappear from your mind.