the boy and/or the girl are dead (the conclusion almost always being "yes"), and how they died (usually said to be a car accident). I guess I can't blame them too much, considering the game's title and all, but there's just so much more interesting discussion to be had than the basic, literal question of "what happened," particularly in a game that roots itself in ambiance to such a degree.
For my part, I view the in-game events as the process of the boy's descent into the same monstrosity as the enemies he continually faces (or, in a more broad sense, a deconstruction of the player's "protagonistic" role in your standard video game, forcing you to do terrible things in your endless quest to move to the right - a key moment for this view being when you must resort to using several bodies floating in a body of water as stepping-stones). The first of these enemies is the spider, which is as overtly malevolent as the enemies get but whose gruesome, hopeless final moments (as well as the moment afterward, wherein you rip off its leg) still evoke a sense of pity. The wild children, meanwhile, indicate that the boy himself is in danger of becoming a willing participant in the harsh world he's trapped in. Not long after moving past both entities, the boy traps a small, innocent dog in a mechanical wheel so that it can power a weather-control machine, thus moving on from the realm of self-defense in order to exploit nature for the sake of his own reckless pursuits. The dangers directly resulting from his use of the machine coupled with the immediately-subsequent, post-apocalyptic urban environment send the message that such acts invariably yield ruin. Later, you reach a high ledge by grabbing a mosquito's leg until you rip it off, mirroring your actions toward the spider; because the mosquito is clearly every bit as innocent as the dog, this moment emphasizes once and for all that even the spider, whether it was truly evil or just trying to survive, is a victim of your own brutality.
Not long after comes the vision of the girl (interrupted by a brain worm), after which there are no further "plot moments" until the ending - which is probably the aspect of the game that has drawn the most criticism. Under this interpretation of the game, though, it makes perfect sense from a story perspective, with the boy having become so ruthless that nothing else in the world wishes to confront him; note, again, the point at which the vision of the girl is placed, and how it ultimately leaves him in solitude prior to the rest of the game doing the same. (Also, another recurring motif is a pair of moths, one flying near the boy and another near the girl, which fly upward offscreen in this scene without meeting up with one another.) He stays that way until the end of the game, where he cannot openly run up and reunite with the girl, but slowly sneaks up behind her in a predatory fashion. Appropriately, the last moment before the game ends is the girl stiffening in alarm and the boy stopping short, showing that in his very quest to reach her, he has irreversibly alienated her.
