WARNING TO READER: Potential spoilers ahead. This is more of an analysis than a review, though I do cover formal elements such as acting, direction, and plot.
Just for a moment, engage in a thought process. Revive old memories through seemingly unrelated ones, relate them, and make sense of them. In fact, you don't even need to be told to do that. An infinite amount of memories and thoughts can be generated in just a moment, so much in fact, that reliving or experiencing anyone's memories, including your own, can be emotionally exhausting and revelatory.
Such a trip is the focus of Eternal Sunshine of the Spotless Mind the latest screenplay from mindfucker extraordinaire Charlie Kaufman, the demented penman behind such delightfully twisted films as Adaptation, Being John Malkovich, and the severely underrated Confessions of a Dangerous Mind. The story revolves around Joel Barish, played by Jim Carrey, who discovers that his former lover, Clementine Kruzcynski, played by Kate Winslet, has completely erased him from her memory. Upon learning this, Joel consults the company responsible for this erasure, Lacuna Inc., to do the same to his memories of Clementine.
The genius of the film is not its concept, but the way it uses reality and memory to tell the story, in a liberal and intertwining fashion that will disorient viewers. Eternal Sunshine's narrative core takes place inside Joel's memories, as he relives them as they're being erased. As he experiences these memories, both pleasant and unpleasant, he decides mid-prodecedure that he would rather the memories of Clementine be unpleasant in context with their relationship, rather than their not existing at all. These memories are connected through a cerebral 'map,' where simple images, actions and sounds (such as a song), will automatically relate back to other memories, which will summarily be deleted.
Necessary to the 'map' method, the memories are deleted in reverse order, and we relive them in this way, and it never feels gimmicky. Joel can guide a memory of Clementine, who moves, talks and acts as Joel desires, and hide her in a memory where she doesn't belong to escape erasure. Also, Joel may be able to relive these memories, but they cannot extend into anything that Joel didn't see or hear at the time that these memories were registered. The scene where he chases Clementine across a street that begins where it ends and vice versa is a good example of this boundary. Joel's memories can overlap, which many can address as a pothole. However, this is perhaps used to reveal to the imperfections of the erasure process, which is a finite procedure that is supposed to eliminate memories with an infinite amount of connections to each other; the memories can exist within each other, for example, one image, action or sound can recall another memory even if that instance of the memory doesn't exist anymore. Other imperfections of the process are revealed in a spoileriffic subplot involving the Lacuna employees. It has been addressed by some as a subplot that is never fully developed, but upon a second viewing (really, Eternal Sunshine is ideal for multiple viewings), you see that the subplot begins development very early into the film.
The story so gracefully retells the relationship that the bizarre backwards transitioning feels completely natural and flowing rather than sudden and confusing. The movie is genuinely funny, tragic, and trippy, all at the same time. We are hurtled in and out of Joel's subconscious and reality more times than we can count, and and every second of it is delightful. His relationship with Clementine is revealed in a reverse fashion, which makes the gradual descent into turmoil even more intense. This order works with the narrative rather than overtaking it. We learn the character's flaws first - Joel is an introvert, he can be boring, self-centered, and withdrawn, and Clementine is a wild, impulsive, and needy- which we later discover is why they loved each other in the first place. Both Carrey's and Winslet's performances have fantastic psychological nuance to them. Winslet perfectly assumes the role as a product of Joel's imagination during the erasure sequences, and Carrey, in a brilliant casting move, puts his rubber-faced neurosis to work here in a role that is the polar opposite of anything he's ever done, save The Majestic.
The effectiveness of the erasure scenes can't be praised without mentioning Michel Gondry's fantastic direction. The entire movie seems to be filmed with a steadycam, constantly capturing a subtle shake, noticeable in a closeup or slow-moving scene. The special effects are wonderfully used as well; the best example is when they are conversing inside the memory of their second encounter, in a bookstore, and the detail on the shelves slowly begins to dissolve as the memory fades away.
'This is the day we met,' Joel recalls as this particular scene, or his memory, opens on a chilly-looking beach party in Montauk. He liked the fact that he wasn't the only one who doesn't know how to socialize, he first fell in love with her back which was a bright red sweatshirt which sharply contrasted with... whatever color her hair was at the time, and she asked for a piece of chicken and immediately took it from his plate. 'You were so into it,' he remembers. Clementine's impulsive and indulgent nature attracted her to him in the first place; personality traits which, tragically, Joel will later consider to be flaws.