The traps awaiting the sequel to an unexpectedly successful comedy are easy to pinpoint, because virtually every such film stumbles into them. Everyone who has seen the increasingly desperate films in the Austin Powers trilogy knows this: the likeliest path for a comedy sequel to take is to recreate the gags from the original movie that it's perhaps better to call it a remake rather than a continuation, and everything is done much louder and goofier the second time around. (It's not even something that just happens to comedies; what is Spider-Man 3 but a louder and goofier take on the same content as Spider-Man 2?)
For a film that seemed tailor-made to do just that, Harold & Kumar Escape from Guantanamo Bay is rather amazingly free of needless retreads from its predecessor, the unexpectedly well-received commercially and critically Harold & Kumar Go to White Castle. Oh, there's still a Neil Patrick Harris cameo as an insatiable drug-using (straight) horndog named Neil Patrick Harris, and a scene with a crazy bumpkin and his improbably gorgeous wife, but that's mostly it, aside from some self-referential one-liners. It's mildly frustrating that the film rolls back some of the character development the titular duo under went during the previous movie - it sets them, let's say, two-thirds through that movie, not all the way at the beginning - but it's hard to imagine a plot working with the characters in exactly the place that we last saw them. The gross-out humor is kicked up a bit and the stoner humor is kicked down, and the gags, though not so fresh as a summer's day in the high sierra, are hardly retreads of the first film.
In the same breath, it's impossible to claim that this film is as good as the first. For it does commit the other sin of the sequel: it needlessly raises the stakes by substantially broadening its scope, and in so doing loses much of the humanity from the original White Castle was an exemplar of one of the great American narrative models: the Long Night of the Soul, in which Harold Lee (John Cho) and Kumar Patel (Kal Penn) undergo an increasingly absurd series of ordeals between sundown and sunup on the way to discovering that they are not the men they thought they were. Guantanamo Bay, in contrast, is more of a frolicsome romp past a countryside of American eccentrics - still a well-worn form, but one that in this case at least is quite a bit shallower. Harold and Kumar do not learn in this movie, they only survive, and the strained happy ending doesn't do much to fix that problem.
There are other scattered points where the new film doesn't quite measure up. It's crasser by far, particularly in the first quarter-hour; notably, I'd mention the quite obnoxious series of gags revolving around Kumar walking in while Harold is using the bathroom that threatens to become a running joke before it's quietly put back on the shelf. Co-directors and writers Jon Hurwitz and Hayden Schlossberg don't have the same sense of comic timing that Danny Leiner did, and a fair number of punchlines show up after we've already figured out what they're going to be. And as you've probably heard, it trivialises the horrors of Gitmo. I'm not about to have the rash stupidity as to argue this isn't the case; by all means, the film's handful of stabs towards political satire are certainly among its most regrettable moments (culminating in a completely nonsensical take on the current administration featuring the worst George W. Bush impersonator I have ever seen). To this I say, "perspective". This is a stoner comedy, and the fact that a stoner comedy would see fit to take on the neo-cons in any capacity strikes me as a nobly foolish stance. It absolutely has nothing of any value to say about human rights abuses under the American military, but imagine how dreadfully it would have knocked the film off-balance if it tried to! As Charles Chaplin said of The Great Dictator, "I'm the clown, and what can I do that is more effective than to laugh at these fellows who are putting humanity to the goose-step." Later, he would denigrate the film as trivialising the Holocaust, so I'm aware that my argument isn't airtight.
Really, though, the only legitimate complaint is that this film takes on politics and flops around, while White Castle had some legitimate insights into how we think of race in the cinema (indeed, the smartest parts about this film are those which revisit those themes, in the marvelously dumbshit racist form of Rob Corddry's Homeland Security director). Insightful this film may not be, but that's never its aim. It's about making us laugh at the silly antics of a couple of dudes we met before and pretty much like. In this, it is decidedly a success. As modern American comedies go, Guantanamo Bay is unexpectedly warm; though the anticipated pratfalls and sick jokes come about by humiliating Harold and (less often) Kumar, that's not the only card the film knows how to play, and the funniest moments are rarely the most abusive. It's a rare thing indeed for a comic movie to obviously like its characters, and there's not a moment that we don't like Harold and Kumar, and root for their success. Our superiority is never mined for jokes, and this alone is enough to recommend the film: though it is raunchy, it is also generous and sweet, and most importantly, it's often pretty hilarious. That's not a combo worth taking for granted.