Sometimes a movie comes along that redefines a genre, that reshapes a movie landscape entirely - a wake-up call to an industry in the form of a seismic pop-culture event which pulls everything else along in its wake.
. . . And sometimes you just get a movie that's a load of self-aware adolescent humor wrapped around cartoonish violence and bare flesh.
Of course, sometimes you get, as Star Lord would say, a bit of both.
Okay, that's an overstatement. Deadpool is a big heaping truckload of the latter and a tiny sprinkling of the former. It's inarguable that the film's marketing campaign and public mindshare has been impressive, and it's record-breaking opening weekend certainly speaks to a well-sold film that delivered the goods to an eager audience. But in spite of the wrong-headed lesson that Hollywood is sure to lean from this ("People want boobs and blood in funny book movies!" "Start having Batman break the 4th Wall!" "Just put Deadpool in everything!"), the movie lands like a perfectly-timed cherry bomb at a frat party for the same reason most big genre hits do.
It saunters up to a curious audience and slaps them across the face with something they never knew that they always wanted.
Ryan Reynolds (who deserves every ounce of the goodwill and success he's seeing from this, thanks to his tireless campaigning to get this thing made against the current of a previously intractable studio) is Wade Wilson, good-hearted mercenary who meets the right girl at the worst possible time. Vanessa, played brilliantly by Firefly's own Morena Baccarin, is the foul-mouthed stripper (or sex worker? The movie's somewhat unclear on the particulars here, which is kinda a surprising feather in its cap, but we'll come back to that) who falls for the man who's "crazy matches hers." The unexpected diagnosis of late-stage cancer is what prompts Wade to seek "help" from a mysterious agency that promises to cure him and even give him superpowers.
Of course, everything goes sideways. But that's hardly a spoiler, as things are already sideways (quite literally) during the film's opening credits, which start in-media res during a bonkers freeway chase sequence in which we see the titular anti-hero in full costume and Looney Tunes mode right off the bat. The aforementioned origin story beats are parsed out via flashbacks, not dissimilar to how the "Clark Kent as a kid" bits are relayed in Man of Steel. Except here, while they're still structurally odd (the entire film has a bit of a "too shaggy for how small it is" feel to it), they still function as a way for the film to have its cake and eat it too. The audience gets to see Deadpool doing Deadpool stuff without having to wait, but still has a character with dramatic reasons to invest in by the time the finale rolls around.
This is one of the film's chief advantages - for all that the movie takes the mickey out of itself, it knows exactly when (and for how long) to get serious. Vanessa and Wade are tremendously blue in how they relate to each other, but the actors play the genuine emotion hiding beneath the snarky exteriors for keeps. It not only gives the humor more range than simply being dick jokes and pop culture references (though there are many of those, to be sure), and allows the film to play at being dumb without actually being stupid.
For example, let's talk about the dramatic rule of "setup and payoff." It's a simple tenet of storytelling that, if you show something early in a story, it should have a function later - "Chehkov's Gun" is an example of adhering to this to remove unneeded story elements. I bring this up, because Deadpool is actually really damn good at this stuff. A lot of the time it's very obviously signposted (one element involving a literal gun has characters joking about it to be sure the audience remembers), but dammit, it's nice to see someone take the time that behemoths like Jurassic World couldn't be bothered with. In a film that could have gotten away with random bullshit more easily than almost anything else in the genre, it's a refreshing surprise that such basic functionality is baked into the adolescence.
The other pleasant touch is how forward-facing certain elements are. Yes, there are gratuitous shots of strippers when the characters go to the strip club, but there's also an entire fight sequence in which Ryan Reynolds is buck-ass nude. Just. . . you know, hanging out. Vanessa is not only not defined by her job as a stripper (or whatever her actual job description entails), but Wade never really gives a shit about what she does for a living and never pressures her to quit, even after they've obviously been together for months. And when the film throws in a female character wearing the requisite "outfit impractical for combat," there's a surprisingly pointed joke at that apparel's expense.
Deadpool does a lot right - not everything, of course. It lampshades it, but the budget really is too constricted for the film to go quite as big as it obviously wants (there are only two actions sequences of note), not all of the jokes land (there's one trans-phobic quip that feels particularly wrong-headed), and while the relationship between Vanessa and Wade undeniably works, the flashback origin stuff never pops as well as the moments where Deadpool gets to go full "Bugs Bunny by way of Fritz the Cat."
But enough of it works. More than enough, and for most of the time. And it's just nice - not nice as in "kind" (Deadpool isn't kind, it's rowdy and nasty and you definitely shouldn't bring the kids), rather it's nice to see Reynolds really get to nail a character who got such crappy treatment in the abysmal X-men Origins: Wolverine, it's nice to see a lot of FOX mutants actually wearing their damn costumes instead of boring black leather, it's nice to see a superhero film embracing the goofy elements of the genre while also poking at them mercilessly, and yes, it's really nice to see Deadpool's success blow the doors of the "PG-13 only" barometer for comic book movie success.
It's also nice to know that parents who do take their kids to this will get to explain what "pegging" is to their offspring.