Do I need to say that it's brilliant? If you've been living in Outer Mongolia and you've never heard of Shaun of the Dead, stop reading this review and buy it in the next thirty seconds.

Simon Pegg is a loser with no future who's about to get dumped by his girlfriend (Kate Ashfield) and whose best friend (Nick Frost) is the missing link between apes and slobs. They live in London, if you call it living. They never do anything. They go down the pub a lot. The film's tagline was "a romantic comedy with zombies" and personally I don't even see it as horror. Horror is trying to scare you. This film merely takes place in that universe, albeit wholeheartedly so and with lovingly rendered blood and guts. You're watching it because it's honest, emotional and funny and because Simon Pegg's the best thing to happen to British cinema in a generation.

This film is excellent all the way through, except when it gets even better. I love the Queen-scored attack. I love the scene where Pegg wanders through a zombie apocalypse to buy a cornetto and never realises it's not a normal day in London. (That's all one long take, by the way.)

I could talk all day about what's obviously great about it, but what particularly struck me this time was the mirroring. We see the same relationships, themes and even dialogue, both before and after the zombie outbreak. Notice how much dialogue from the film's second half shows up in a different context in the first, before hell's broken loose. "I'm glad someone made it." "I'd only hold you back." Serafinowicz tells Frost to "go and live in the shed." This matters because it's at the heart of the film that fundamentally nothing gets changed by the zombie apocalypse and that it wouldn't alter much if all the dead-end people were themselves dead too.

The exception is Pegg. He changes, but then again he made that decision before learning about the zombies. If you can see past the gore and gags to Pegg's character development, you'll see for instance that Bill Nighy's (touching) last speech in the car is even more important than it looks.

The cast is top-notch, not to mention full of people from Spaced and other British TV comedies. That's true even of Jessica Hynes's group of non-speaking cameo characters we meet for about thirty seconds in the middle of the film, who include Martin Freeman, Reece Shearsmith and Matt Lucas. Simon Pegg is obviously a star and it's no surprise at all that he's gone on to massive success. Bill Nighy and Penelope Wilton represent the older generation and both provide emotional weight when the time comes. Even the filmmakers were startled by how powerful Wilton's final scene turned out in shooting, although of course that's due to Pegg, Dylan Moran and the others.

Incidentally, Shaun and Ed's friendship is based on Simon Pegg's and Nick Frost's when they shared a flat together. Cool. Also Pegg and Wright considered a sequel with another monster instead of zombies, about which I'm torn. I'd have loved to see that, but I also approve of their decision to let this film stand alone.

The obvious comparison is with Hot Fuzz, the second in Pegg and Wright's Blood and Ice Cream Trilogy. (The third film is due in 2014 and to be called The World's End.) Personally I prefer this to Hot Fuzz, although of course that's a fine film too. I'm a fan of horror, not action films. Horror isn't an intellectual genre, but it's a powerful weapon for tackling themes and emotionally powerful storytelling to yield an effect you can't get any other way. Action films strike me as emptier, although I admit that that's largely my prejudice.

Talking about it here, I've realised that it's one of my favourite films. It's a slick, good-looking movie with better acting, writing and even cinematography than you'd expect in a zombie flick. (The cellar finale in particular has some beautiful shots.) It's well up on its horror lore. It's got a solid, clever script that won awards, but it's also a laugh and great fun on the surface too.

I love its moments. I love Nighy turning off the music in the car. I love Pegg's face when he says "lots".

"Next time I see him, he's dead."