For Ryan Reynolds, third time is the charm as he at last fulfills his superhero destiny with Deadpool, based on the anti-hero created in 1991 for Marvel Comics by Fabian Nicieza and Rob Liefeld. After an abortive first attempt at bringing some sort of version of Wade Wilson to the screen in X-Men Origins: Wolverine, followed by his disastrous portrayal of Hal Jordan in 2011’s Green Lantern, Reynolds has returned to Wilson – the character he was born to play – in a movie that he has spent several years with director Tim Miller and writers Rhett Reese and Paul Wernick practically willing into existence.

Now here it is, in all its crude, ratty glory, and we can tell you that Deadpool the movie has at least nailed both the tone of the comics and the ragged charm of the character himself. As Wade says himself early in the film (after a brilliant and hilarious opening credits sequence), he’s not a good guy; he’s a mercenary, a bad guy who gets rid of worse guys. But he’s fun to be around, he’s quick with the quips and the meta references, he breaks the fourth wall to speak directly to the audience (as he has done so famously with the readers of his comic books) and – as we find out when he meets the woman of his dreams, Vanessa (Morena Baccarin of Firefly and, more recently, Gotham) – he’s a romantic at heart.

The movie opens with Deadpool on his way to meet and rough up some of those bad guys we mentioned earlier. And we do mean rough up: there is very little in the way of a moral code about killing in Deadpool’s addled brain. He decapitates and disembowels his enemies with gleeful abandon, and is more than willing to torture the ones that survive. Eventually we find out why he’s after lead baddie Francis/Ajax (Ed Skrein) – who, like Wade, has been mutated and given enhanced powers by a secret program that Wade volunteered for, with the reason disclosed in flashbacks.

It turns out that Wade submitted himself to the experiments in order to cure the Stage 4 cancer he’s been diagnosed with, but in addition to giving him remarkable healing powers and strength, the process has scarred him horribly and left him mentally unstable. Rather than reveal his hideous appearance to Vanessa, he allows her to assume that he is dead and creates the Deadpool persona (and a dead-on costume right out of the books) so that he can track down Francis, whom Wade believes can restore his flesh to normal. Along the way he gains the attention of the X-Men, represented by metal-skinned Colossus (voice by Stefan Kapicic, motion capture by Andre Tricoteux) and the rather explosive Negasonic Teenage Warhead (Brianna Hildebrand).

That’s the extent of the plot, much of which plays out as a standard origin story — only filtered through the worldview of Deadpool/Wade, who is just as aware as you that he is a fictional creation. Reynolds gives his all in the role, and it’s clear from the start that he has immersed himself in this character and worked to create the perfect screen version of Deadpool. He’s endlessly carrying on a running conversation with himself (“Did I leave the stove on?”), reacting like a petulant child when he gets shot or stabbed, and riotously commenting on the comic book movie world around him — including several jokes at the X-Men franchise’s expense.

The movie basically is a one-man show and director Miller wisely derives almost all its entertainment value from Reynolds’ detailed and truly oddball performance, which luckily powers through a production that is otherwise fairly threadbare. A friend noted after the press screening that Deadpool operates in fours: the movie more or less consists of four characters, four scenes, and four sets/locations.

We spend a hell of a lot of time on that one freeway set where the opening confrontation takes place, and the only other major action set piece — handled adequately if unspectacularly by Miller — takes place at the end, in a dingy shipyard atop something that should give sharp-eyed Marvel fans pause. Wade and Vanessa’s apartment and the bar belonging to Wade’s sidekick Weasel (T.J. Miller) are cramped and dark, while the Weapon X lab looks like they just redressed the bar. For a mutant with such a big mouth, Deadpool’s world is decidedly small.

The rest of the cast never quite gets out of the shadow of our star either, and the script (by Zombieland scribes Paul Wernick and Rhett Reese) doesn’t do much to help them. Baccarin is playful and sexy but ultimately her Vanessa (who is the mutant Copycat in the comics) becomes just another girlfriend in danger, while Miller’s Weasel is there simply for Reynolds to play off of. The CG Colossus could have used one more pass through the hard drive, but comes across as reasonably lifelike and has a few good lines. Sadly, in grand Marvel movie tradition, the villains fare the worst: Skrein’s Ajax is a generic, shaven-headed bad guy with a British accent and a murky motive, while Gina Carano’s Angel Dust barely registers except for one cute moment near the end.

With the main character’s over-the-top-and-beyond behavior and constant self-awareness dominating the proceedings, it’s too easy to think that Deadpool could be a game-changer of some sort or an antidote to the sometimes ridiculously grim gravitas of a lot of today’s superhero movies. Sure, it’s a welcome dose of comic relief, but it’s too small a movie to rest that burden on its red-clad shoulders. And besides, in the end it’s still a one-trick pony, as enjoyable as that trick is (and at 106 minutes or so, it doesn’t overstay its welcome).

Deadpool is fun, highly entertaining and, for fans of the comics, does exactly what it promised — nothing more or less. Oh, and make sure you stay until the very end — the post-credits sequence isn’t the one you might have expected, but it’s the one you deserve.

Deadpool is out in theaters this Friday (February 12).