There's still a ton of unanswered questions surrounding Braid, the more philosophical of which will likely remain unanswered for a long, long time. However, if you're perplexed by the technical side of the time-bending indie darling, check out a video of Jonathan Blow's Game City panel below.
Braid is a puzzle-platformer, drawn in a painterly style, where the player manipulates the flow of time in strange and unusual ways. From a house in the city, journey to a series of worlds and solve puzzles to rescue an abducted princess. In each world, you have a different power to affect the way time behaves, and it is time's strangeness that creates the puzzles. The time behaviors include: the ability to rewind, objects that are immune to being rewound, time that is tied to space, parallel realities, time dilation, and perhaps more. Braid treats your time and attention as precious; there is no filler in this game. Every puzzle shows you something new and interesting about the game world.