Braid is played by solving physical puzzles in a standard platform game environment. The player controls the protagonist Tim as he runs, jumps, and climbs across the game's levels. Tim jumps and stomps on enemies to defeat them, and can collect keys to unlock doors or operate levers to trigger platforms. A defining game element is the player's unlimited ability to reverse time and "rewind" actions, even after dying. The game is divided into six worlds, which are experienced sequentially and can be entered from different rooms of Tim's house; the player can return to any world previously visited to attempt to solve puzzles they missed.
Each world has its own time-based game mechanic:
Time and Forgiveness plays as an ordinary platform game, except that the player may rewind time to undo their actions. The section includes several challenges that would be unplayable or unfair in an ordinary platform game, but become feasible when the rewind mechanic is available.
Time and Mystery introduces objects surrounded by a green glow that are unaffected by time manipulation; for example, switches will remain flipped even if time is rewound to before the action occurred. Rewinding can thus be used to change the synchronization between objects that can and cannot be rewound, the basis of many puzzles in this section. This theme is also used in later worlds to denote objects unaffected by the player's time manipulation.
Time and Place links the passage of time to the player character's location on the horizontal axis. As the player moves toward the right, time flows forward, while moving toward the left reverses the flow; standing still or moving vertically will pause time. The player's location must be carefully managed in relation to enemies and objects.
Time and Decision involves a "shadow" of the player character appearing after the player rewinds time and performing the actions that the real player character rewound; if the timeline expires, the shadow will complete any initiated falls and jumps but will otherwise stand still before disappearing. Things coloured in violet can interact both with the main character and his shadow at the same time. Puzzles in this section revolve around using this mechanic to carry out multiple actions at once.
Hesitance provides the player with a magic ring which, when dropped, warps the flow of time around itself; the closer moving objects (including Tim) are to it, the slower time passes for them. The regular rewind control remains available.
The final world is labeled simply "1." In this world, time flows in reverse. Rewinding time returns the flow of time to its normal state.
Each stage contains puzzle pieces that must be collected to create jigsaw puzzles that tell the story, and to unlock the last stage. On completing the main game, a speedrun mode becomes available for select levels and the entire game. There are also eight stars hidden throughout the world of Braid that correspond to the stars in the constellation of Andromeda just outside the main character's house.
Plot
Tim is a man searching for a princess who "has been snatched by a horrible and evil monster." His relationship with this princess is vague at best, and the only clear part of this relationship is that Tim has made some sort of mistake which he hopes to reconcile or, if possible, erase. As one progresses through the six worlds in Braid, storyline text at the beginning of each world provides further insight into Tim's quest for the princess, and alludes to the overarching gameplay mechanic of each level. The themes evoked include forgiveness, desire, and frustration. The final level, in which everything but Tim moves in reverse, depicts the princess escaping from a knight, and working together with Tim to surpass obstacles and meet at her home. Tim is suddenly locked out of the house, and, as time progresses forward, reversing Tim's actions, the events show the princess running from Tim, setting traps that he is able to evade, until she is rescued by the knight. Tim is revealed to be the "monster" the princess is running from.
Following completion of the game, the player finds additional texts that expand the story. The ending of the game is purposely ambiguous, and has been subject to multiple interpretations. One theory, based on the inclusion of a hidden event and the famous quotation stated by Kenneth Bainbridge after the detonation of the first atomic bomb—"Now we are all sons of bitches"—is that the princess represents the atomic bomb and Tim is a scientist involved in its development. Some also refer to the name of the game as both reference to the hair braid of the princess Tim seeks as well as the intertwining of time, demonstrated by the various time mechanics explored in the game. Journalists have considered Braid's plot to be interwoven with the game itself, much as the book Dictionary of the Khazars and the films Memento and Eternal Sunshine of the Spotless Mind interweave the narrative into the work's construction. In this sense, some have considered the game to carry a simple credo, such as "You must look back to go forwards" as suggested by Eurogamer's Dan Whitehead. Others have likened Braid to punk rock, designed (as explicitly stated by Blow) specifically as a statement against the status quo of the industry; it is considered to deconstruct traditional gameplay concepts, such as jumping on enemies or rescuing a princess from a castle as borrowed from Super Mario Bros., and rebuild them in the game to force the player to rethink current game design. Blow has stated that there is more than one interpretation of the story; he "would not be capable" of explaining the whole story of the game in words, and said that the central idea is "something big and subtle and resists being looked at directly." Blow considered Braid to be "about the journey, not the destination". He deliberately designed the plot not to be fully revealed to the player unless they completed the game, seeing it as a way to provide "a longer-term challenge".
