The best part about Men in Black 3 - I doubt anybody would be violently driven to disagree, and I also doubt anybody would be terribly surprised - is Josh Brolin giving a performance that is at once a parody of Tommy Lee Jones, and an homage to Tommy Lee Jones, and a sincere attempt to find what he can make his own with a character that has already been given life by another actor, in this case Tommy Lee Jones. I suppose by now you've also heard that Brolin is not the only good thing in MIB3, and this did come as a surprise, to me at least, given what might have been.

In fact, yes, I think I misspoke somewhat: the actual best part about MIB3 is that it isn't Men in Black II (and now's as good a time as any to point it out: they did very definitely switch from Roman to Arabic numerals in the title, and I have no idea why). This is a very low bar to clear, and it's maybe not fair to give the new film points just for not being even remotely as bad as its 10-year-old predecessor, because literally thousands of movies meet that definition. Incidentally, I'm not going to what I'd expected to, and slag on MIB3 for coming out after a decade-long break; MIBII itself came out five years after the generally lively, playful, creative, and all-round quality '90s blockbuster Men in Black, and if having twice as long a gestation period is the reason that MIB3 does not suck so hard, then I hope they put off Men in Black 4 for a solid 20 years, and maybe we'll really have a movie going.

But back to matters at hand: the new film requires very little knowledge of the first two in order to get going, and that's awfully decent of it. What we have is, Agent J (Will Smith) and Agent K (Jones) of the shadow government group Men in Black, that tracks the lives of all extraterrestrials living on Earth, have been partners for years and years and years now, and J is getting old enough himself that he cannot fathom how old K must be, given that K was already ancient when they met; and he's also getting frustrated by his partner's refusal in 14 years to share even one detail of his personal life. K is doing some stock-taking of his own: his dear friend, MIB chief Zed, has just passed on, leaving control of the group to K's old flame O (Emma Thompson), and one of his first big cases as a Man in Black has just come back up, as the insane alien criminal Boris the Animal (Jemaine Clement, unrecognisable behind latex and channeling Tim Curry's voice) has just managed to escape from a high-security lunar prison with revenge on his mind against the man who put him there.

This revenge takes the form of going back in time to kill K before any of this happened; for reasons that are too-foggily explained, J is the only person who realises that he's living in an alternate timeline, and soon he zips back, too; all the way to July, 1969, when Boris first surfaced, and a much younger though still shockingly craggy K (Brolin) was just an up-and-coming agent, and there's a plot involved in all of this but the vast majority of what makes the film appealing is that Smith and Brolin just get to hang out and toss barbs at each other, just the way that Smith and Lee did in the first movie way back in 1997, only this time there's a lot of meta-humor as well. Eventually, it all culminates in an action sequence set against the backdrop of the Apollo 11 launch, for reasons that actually make a fair amount of sense given the parameters the story has set up for itself, and does not in any way whatsoever make a complete mockery of the Apollo program or NASA itself, unlike some other recent summer movies involving Apollo 11 that I could name.

But again, the main draw is the hanging out and goofing around, something Smith does really, exceedingly well, and hasn't gotten a chance to do recently - primarily because he hasn't made a movie since 2008, and secondarily since he last film at that time was the dour, irritating drama Seven Pounds. In fact, I should say that Smith hasn't been having this much obvious fun since at least 2003's Bad Boys II, if not the original '97 edition MIB itself. And it is good to be reminded why one of our few great contemporary movie stars is so invaluable, so the film is doing the Lord's work on that front, at any rate.

What this does mean, though, is that it's the middle part of the movie that is far and away the best, and thankfully it is also an extended middle; but the opening and closing sequences are not nearly so good. The film is just straight-up death until J jumps to 1969, some 25 or 30 minutes in, owing in great part to how obviously Jones is not having fun making one of these (correct my memory, but wasn't one of the big issues with MIBII the amount of negotiating and compromising it took to get him back in the suit at all?), and somewhat less to director Barry Sonnenfeld's apparent rustiness at directing light action: the 1990s, when he made fun, fizzy pictures like Get Shorty and The Addams Family and Men in Black itself, were a very long time ago, and he hasn't made a feature since RV in 2006. It is merely natural that he should have become a bit rusty in all of that time, and so it is: even when MIB3 clicks, it has a lot more to do with the acting than the directing, which is a bit brittle at all points. Though, to give the man credit, it's also shockingly slow, in a good way: as comedies and action movies have gotten so much more hectic since Sonnenfeld's heyday, it's easy to forget how damn laconic even big tentpole movies used to be, with nice, decently long takes and stretched-out dialogue moments, and that the filmmaker doesn't see fit to rush us through any of this is a real pleasure.

But yes, there's still a lot of deadweight, and while I liked that screenwriter Etan Cohen takes the mechanics of his plot so seriously, I would not have minded at all if he'd maybe figured out a way to have those mechanics work faster. The new film suffers the exact same problem as the first, which is that the third act becomes so plotty and so concerned with action and incident it stops being funny (the second film also suffered from this, but it was the entire feature, not just the climax), and the attempt to resolve all of the emotional material from the early going absolutely dies in the face of logic and plot coherence and, for that matter, chronology (though chronology is not a strong suit here: after I don't know how many references to "over 40 years ago", J claims to have traveled 39 years - 25 plus 14, specifically).

Still, despite all of that, MIB3 is a fun, blithe summer romp of the old school, with lots of terrific Rick Baker make-up work, and better-than-average CG, and plenty of reasonably witty moments that don't assume the audience is too smart and, importantly, doesn't assume we're too dumb, either (there's an extended sequence at The Factor, with Bill Hader putting in a fine cameo as Andy Warhol, that requires far more specific knowledge of '60s culture than I would expected a big studio film to assume of its audience, and I suppose its partially for this reason that it's arguably the film's highlight). It's not nearly as good on any level as the first movie was, but a 15-years-later sequel doesn't have any right to be involved in that kind of conversation at all, and the mere fact that I feel comfortable saying that MIB3 is merely "not as good as Men in Black" is quite an achievement, all things considered.