Alan Moore's graphic novel masterpiece has always been considered unfilmable and perversely, Zack Snyder has proved it! It is an excellent film though. Bright and vibrant, it marks a step forward for the genre and Snyder's reputation. At its best, it's the sort of film Scorcese would make if he did comic book movies (and no, that isn't just because of Travis Bickle-esque Rorschach).

The book has been adapted very well, except it misses a defining voice. The comic teases out the plot in only the way a comic can, with a sort of "third person" perspective and it just doesn't lend itself to a film narrative which has to keep switching. The plot comes across as confused and the Rorschach's Journal device sits awkwardly with the other strands. The comic had a story-within-a-story idea with The Tales of The Black Freighter and this really helped pace it. Apparently the Ultimate Cut of the film puts the animated version of this, but that would make it even longer! So at its worst, it's bloated and unfocused, but at least it's a good advert for just how progressive and brilliant comic writing can be.

But we should focus on the film, because despite this fundamental issue, it still works. It's a character piece rather than action so casting was paramount. Patrick Wilson as Nite Owl, Billy Crudup as Dr. Manhattan and especially Jackie Earle Haley as Rorschach are superb, but there isn't a duff note from any of the cast. After the success he had with 300, I'd thought Zack Snyder would have similarly treated this with digital style over substance, so it's impressive that it feels very solid, with old fashioned photography at times which comes alive on the Blu-Ray transfer, and the actors are given room even in the action scenes, which are largely bone-crunching, gravity defying fights. In fact, I should take a step back: this is far superior in all respects to 300, and that was great fun! I loved the soundtrack and the frequent juxtaposition that the film found within the plot. It's evocative of the 80s and the emphasis is on quality film composition, not set-pieces, with cool effects taking the background more often than not. The detail is on a massive scale, especially with press cuttings and in the flashback sequences.

It is very much a film designed for cinema, and not just a knock-off rerun of the book; the changed ending demonstrates this, as it feels organic. I prefer the comic, but kudos for making such a bold move. If I was being really picky, I'd have preferred less slow-mo. Heck, Snyder could have shaved 20 minutes off the running time, just by using normal speed! But slow-mo or "normal-mo", the effects are fantastic, particularly on the big blue Doctor (plus no cheesy attempts to hide his nudity, which is essential to the character) and it's commendable that the cast are not swallowed up.

Snyder obviously loves and respects the source material and treats it with confidence more than reverence, but his film is just too long. Yet, parts still feel rushed and I can't think what could have been easily lost. That's why it would never have worked perfectly, but be in no doubt that Zack Snyder has done a marvellous job that I doubt others could have even matched.

It will be forever compared with the book and so Zack Snyder's very fine and adult film, which marks him out as a serious talent, is merely an also-ran when put next to Nolan's Batman films or even Kick-Ass. A real shame, because Watchmen makes Mark Millar's story look positively naive and juvenile. Still, it does rank very high, certainly above the Spider-Man and X-Men movies. All its problems come from trying to adapt the Citizen Kane of comics and Snyder has done a Peter Jackson level of work to produce as good a film as possible.