I just have to say this; the opening to Dredd is awful. It's just really, really bad. It consists of a freeway chase and a mall shootout, and while the action is decently staged, it in no way, shape or form looks like the kind of world Judge Dredd should be operating in. It looks like it's taking place in a particularly rundown section of contemporary Los Angeles. It's about as underwhelming as an opening can be, really.
Which is annoying, because the rest of this movie is pretty great.
Dredd (not 3D, thank you very much) takes a fairly standard action cliche plotline and puts its own twist on it. Two cliches, actually. First, Dredd, the gruff and experienced veteran, is saddled with a promising but unpolished rookie partner. Second, what looks like a routine bust turns out to be much more dangerous, and Dredd and said partner have to fight their way through the gang's mooks and a sullen, uncooperative local populace to escape. Neither of these are ground-breaking ideas, obviously, but director Pete Travis knows how to work with his setting and stars to sell it. Which is no small feat, of course, given that unlike Stallone, Karl Urban is completely committed to the idea of Dredd never taking his helmet off, or showing any expression other than slight variations on his default Epic Frown. You'll honestly be amazed at how much you can convey with nothing but subtle changes in the intensity of a scowl. It's great.
The cast is pretty stripped down, as befits this kind of story. Alongside Urban's Dredd, Olivia Thirlby does a solid job as Judge(-in-Training) Anderson, managing to make it believable that the little blonde ingenue could, in fact, be tough as nails. Their interactions are understated, but all the more rewarding for that when they do have a serious conversation. Thrilby nicely manages to make Anderson innocent without being ignorant, and the script does a good job of having her come off as a smart, resourceful Judge who just doesn't have any real street experience. At no point is Anderson The Chick to Dredd, and she even has a few little tricks at her disposal that Dredd lacks. And Thirlby does a great job playing off against Urban. There's an undercurrent to their relationship, a hint that perhaps she's looking for a little more validation than just a passing grade on her practical exam, which in a less capable actress' hands could have easily come off as Anderson having a crush on Dredd. Here, thankfully, it's far less cliched, or at least it's equally cliched, but using a less awful one given the situation.
Aside from the Judges, there are really only two characters, and I'm not even kidding; pretty much everyone else is just 'Homeless Man', 'Paramedic', 'Woman in Window'. It's a really, really small cast. Wood Harris plays Kay, a mid-level criminal operative whose arrest gets the plot going. Harris is clearly enjoying the opportunity to play an unrepentantly awful person, and it makes Kay someone you really do love to hate. His interactions with Anderson are particularly good, as he really ratchets up the terror behind the idea of a Judge being trapped in the very heart of a criminal empire, while she does her best to shut him out and, not too subtly, resist the urge to shoot him just to shut him up. The other meaningful character is Ma-Ma, head of the criminal empire the two Judges have stumbled into. Ma-Ma is a strange character, with a strange backstory arc, and Lena Headey plays her with a sort of detachment for the most part. When things are going fine, Ma-Ma seems content, almost a little bored. But as soon as a problem or a threat surfaces, Headey switches from laconic to ferocious, really selling the idea that a scrawny, listless thing like that could be capable of the ruthless violence necessary to secure the top spot in such a situation. For obvious reasons she spends most of the movie separated from the two Judges, limiting Headey mostly to acting against mooks and extras, but when Ma-Ma, Dredd and Anderson's paths do eventually intersect, Heady holds her ground quite well with the other two, but without overshadowing them with her bigger, more extreme character.
It goes without saying, of course, that Dredd is violent. The movie particularly likes to shift into slow motion when the gunfights start in earnest, showing off every spurt of blood and explosion of concrete dust from just about every bullet fired. It's not grotesque, but it is kind of extreme; I'm not sure I'd recommend this movie to anyone who's squeamish. It's not really a spot of the old ultra-violence, but it's not bloodless carnage, not by a long shot.
It's a shame this movie wasn't better received, as it really is quite a good action film. Sadly, from all I've been able to gather, most of the early press couldn't seem to drag the image of Judge Dredd away from Stallone's hammy, ludicrous portrayal, which almost nobody was really looking to see more of. But if you like the Dredd comics, or just the idea of Dredd being done seriously, this is definitely a movie worth checking out. Or heck, if you just like vaguely scifi, action-adventure or cop movies, it's worth it for that, too.
Basically, what I'm saying is, go watch Dredd! And don't worry about the 3D; the movie works just fine without it, and it's dark enough I can't imagine the action would be all that clear in 3D.