Thanks largely to Jorge and David Carlton, I have been thinking about the idea of "maturity" in video games. Fortuitously, Jorge and David happened to get this discussion started as I was finishing up Braid.It is difficult to pin down what constitutes a "mature" game. The ESRB uses the word to describe games with explicit violence, naughty language, or nudity. Others argue that a mature game should speak to societal issues and seek to be something more than a mere diversion from the outside world. Some say that maturity is tied to the rules of a game and the skills necessary to succeed within a limited framework. I suspect there is no single answer, which makes me less guilty about advancing another theory.
Braid's use of artistic, thematic, and structural allusions to other games demonstrates an awareness of both the medium's history and its potential for growth. Braid's references go beyond simple tributes: they are tools that help define, and also challenge, the concept of "gaming literacy." Braid's maturity stems from its engagement with other games, as well as with the players' expectations.
Braid's art evokes Super Mario Bros., which serves to usher experienced gamers into a familiar world while simultaneously paying tribute to the world's antecedents. The most prevalent enemy is a round, two-legged baddie that attacks the player in a brave, yet suicidal, fashion. 
The landscape is dotted with green pipes that hide killer plants that nip at Tim's heels as he vaults them. A world's end is marked with the traditional flag, castle, and pseudo-reptilian occupant. The game is littered with symbols encoded with years of cultural significance in regards to games: little baddies are for jumping on, spiny plants will hurt you, and the princess is being held in the castle by a dragon. Braid welcomes old players in with honest tributes to fond memories, while also ushering new players into traditions that constitute the foundation of video game culture.
Almost immediately, Braid shifts from a simple tribute to a work dedicated to exploring the themes behind this imagery. Rather than a spiky, flame-breathing Bowser character, Braid's castles are inhabited by a helpful plush-doll-like dinosaur. The Greeter is an aesthetic contrast to a Super Mario-style end-level boss and it becomes clear that the character has no interest, motive, or even ability to act as an antagonist. 
The Greeter's soft, stitched-together look gives it a visual honesty that mirrors its thematic purpose. The first time the Greeter suggests that the "princess is in another castle," it is easily written off as a joke reference. However, as the game wears on, it becomes increasingly clear that this simple stuffed doll is speaking the plain truth: not only is there no princess in this castle, there may be no princess at all.
As both a platformer and a video game, Braid is surrounded by other works whose themes have remained remarkably static over the years. Whether it is an Italian plumber or an armored space marine, there is almost always a bad guy, a good guy, and a damsel in distress that needs rescuing. Any obstacles to the aforementioned damsel are attributed to the antagonist as a foregone conclusion. The game avoids this simplistic trope and constructs a morally-ambiguous plot, one that recognizes challenges the player to consider the thematically-mature concept of a world painted in shades of gray.
Because Braid is a game, these visuals and themes are explored through interactivity. It is here that Braid's sophistication is most impressive, as its intertextuality stems from the gameplay itself. Sometimes, this manifests as direct references to other games in the form of timing-based jumps, or the physically nonsensical (yet extremely well-established) action of gaining jump height by spring-boarding off of enemies.
Braid's novel time manipulation mechanic lays bare both the absurdity and beauty of long held gaming conventions. No one needs to read the instructions to learn that fire pits are deadly, but even if they make
a mistake, they can rewind time and bring Tim back to life in a way nearly identical to how one would rescue Mario from an errant jump. The difference in Braid is that, in addition to being mechanically acknowledged, resurrection is also artistically and thematically integrated into the game and the notion of player progress.For decades, progress in side-scrolling games has been implicitly defined as movement to the right side of the screen. Moving to the left (when it is allowed) has traditionally been a way to "reset" the game and bring back enemies and platforms that the player previously dispatched. In world 4, Braid confronts this idea from a novel perspective: When moving to the right, time travels forward, when moving to the left, time goes back.
However, Braid is most interesting when it uses traditional gameplay conventions to challenge players' the gaming literacy they have acquired over the years. One of the most striking examples of the game's ability to undermine gaming tropes and player expectations is in the "Jumpman" stage. Here, all Braid's intertextual qualities are on display: the level takes its name from Mario's original moniker and contains a structure built in the image of the original Donkey Kong game. An artistic representation of a giant ape resides at the top of the structure, but the thematic allusion is given a twist via the princess's absence.
This notion of the subverting the familiar is made explicit when the player attempts to scale the platforms in the tradition of the original Donkey Kong. No matter how good their jumping and running skills are, it is impossible to overcome this task the way a conical source has trained us to play it. Instead, we must use the game's mechanic to break from tradition. The puzzle requires the player to literally and symbolically venture outside the traditional boundaries of the game. Playing "Jumpman" in Braid is to deconstruct Donkey Kong and then play it in a new way.Braid walks a thin line between being indulgent self awareness and thoughtful self reflection. While it is not always humble, it a game that explicitly engages with the player's expectations and the works that preceded it. It is a game that mixes deference to tradition while also challenging the complacency that such deference breeds. Striving to maintain its balance with one foot in the past and one in the future, Braid makes a subtle commentary on the culture in which it was created, thereby demonstrating a maturity that transcends sex, gore, and profanity.
