It's somewhat comparable to the ratings system for movies (PG, 14A, etc.), except, as mentioned above, the ESRB is broken and doesn't complete the task as effectively. That aside, language, violence and sexuality are the dominant factors that push a game to be rated M. Drug use, although rare in video games, is likely to drive things up as well.

As for "Mature" games, the word is subjective. I think the intent was to indicate that those games dealt with content that required a certain measure of maturity from the audience to understand the issues/views/material that the game explores. And by 'understand', I mean philosophically so; such as the diametrically opposing themes of feminism and misogyny in Heavenly Sword. An immature mind might just ogle at Nariko and see nothing wrong with the sexism she deals with throughout the game.

But as I already said, the system is broken, and 'maturity' is subjective. There are plenty of thirteen year old boys who will still hold women with the proper respect they deserve in spite of some material they are exposed to. And some guys well into their twenties could learn from these kids' examples.

Well, my train of thought sort of meandered a bit. I guess in conclusion, I can see what this rating system is trying to achieve and I don't disapprove with their goal. However, they need more rigid standards like the ratings' folks with movies, and people should give younger gamers some more credit.

I'm with you on this one.  I don't mind if a women wears a skimpy outfit in a game but in games, and fiction in general, I prefer substance over style on females characters(as well as male characters).

I think the use of drugs, vulgar language and nudity plays a huge role in why some games are considered to be "mature".

sex,violence, blood and gore, drugs, and bad language.

Man Starship Troopers was a giant block of satire

Haha I wrote a huge thread on this before summer and it pissed a lot off that I called games like God of War immature. Really it's true most M rated games are geared towards the 16 to 25 range gamer that doesn't like anything but intellectually void movies, books, and activities and love those over the top R rated action movies and want as much violence as they can get from a video game.

Then you have E rated games that are built geared towards adults and provide a learning experience, some morals, and theories on the world itself. Much like the Earthbound series, there's a philosophy behind it, a lot of ideas, and it's all wrapped up in a very stylized and artsy type game.

Mostly blood, gore, and swearing.

I almost entirely agree with Rocketpig, who I haven't talked to in forever and missed a great deal, btw.

This can comprise anything from Tetris to Chess to Braid.

Braid is one of the few "OMG ART!" games in recent times (including MGS, Bioshock,GTA and a few others) that I felt actually was reasonably sophisticated. We're not talking Shakespeare yet, here, but baby steps are good. As someone who has become disgusted with the facile, sophomoric stories that game reviewers have become fixated on, that was a pleasant surprise.

I'd also likely include something like Wii Fit, which does not work your brain, but does work your body. Concern over health and fitness is definitely a mature concern. This one is arguable, though.

Man appreciating Starship Troopers for what it is isn't THAT bad. There's more to it than boobies!

And I would defend Bioshock's storytelling. It's the first game that ever made me want to put the game down and stop playing - not because it was bad, but just to spite one of the characters. The plot twist played nicely with how we approach games.

Bad words, is naughty which is why games are glue'd to M. :P