A character-driven epic with many layers. *spoilers*

Rating: 9/10 (3 March 2004)

A simple plot here, the easiest thing to "get". The movie opens with childhood friends Jimmy (Penn), Dave (Robbins), and Sean (Bacon) having the course of their lives change right before their eyes as one of them (Dave) is more or less forced into the car of an assumed sexual offender. The story then picks up many years later and everything comes to a head when Jimmy's daughter is brutally murdered, which brings back bad memories back for everybody, while Sean and partner Whitey (Fishburne) have to get to the bottom of it all.
As said, the plot isn't too complicated and there are even a few holes one could point out in the story, but all of that is merely secondary. Eastwood and company focus more on the themes of murder (as advertised in the original trailer), justice, vengeance, and of course the multi-layered characters. Many fault the movie for the "weak" plot, but these people are missing the entire point of why this movie was made. Mystic River gives you just enough story and lets the characters do their work and do it well. The result is an emotional barrage that takes the mature viewer places they never expected or maybe never wanted to go.
The acting is of course the strong point and this may be the best ensemble cast anywhere. Penn plays the emotionally charged Jimmy so well, in that you can feel how broken up he is about his daughter, and just see the sorrow in his face, while in another moment he can be downright menacing - the saying 'if looks could kill' coming to mind. Penn makes the switch between "sides" so naturally and believably, he deserves any accolades and praise coming his way (I hear he won the Oscar). Robbins much to my surprise was just as good as Penn, if not better. You see the pain in his eyes and in his walk, but at the same time are upset because his character portrays that of a liar many times in the film, making you unsure of whether you want to see good or bad done to him. Bacon is the least featured of the three, but he plays his role very well considering what's given to him. Marcia Gay Harden and Laura Linney are very good too, neither Oscar worthy, but one to keep your eye on might be Tom Guiry, who played the boyfriend of Jimmy's daughter. Guiry was very much engrossed in his character like Penn and Robbins were into theirs, which is saying something. Fishburne's part was so small that I nearly forget him, though he does his job fine, like Bacon.
The themes and symbolism here will probably make this one to re-watch for years to come. For instance, when you find out about one of the culprits in particular it all comes together, as he bore a resemblance to Dave, and by coincidence or not ended up being the bearer of penance to Jimmy for all his sins. Or going back to the theme of murder, and how ironic it was to see Brendan (Guiry) become as chilling as Jimmy as the result of both losing the same person. The ending with Linney was controversial, but perfectly in context I thought. Her speech hammers the themes touched on throughout and makes you ask questions. Was it really bad for Jimmy's wife to feel this way after not only going through the trauma, but after the viewer at one point surely wanting vengeance too? Would it be that "evil" of a speech if Dave really did do it? Why or why not? Dozens more examples and questions could be raised from this masterpiece.
Eastwood's directing is impressive, as he never judges the characters, and instead leaves that up to you. Clint's objective viewpoint works, considering the moral dilemmas brought up, but even so, it isn't quite Oscar-worthy. As beautifully shot as Unforgiven though.
If there is one fault however, it is the pacing of the movie, which at one point, gets very, very slow. While the plot itself takes a backseat, and the slow build makes sense for the gradual change with everyone involved, one just can't help but feel that Mystic River would've benefited from a slice here or there. But a patient person that understands this movie will not find it to be that much of a problem. Highly recommended. 9 or 10/10
I also recommend Taxi Driver (10/10) if you liked this, as it's in the same vein, and also American Psycho (7/10) to a degree - though opinions on the latter are more varied, plus it's more of a dark satire in comparison.