Just saw it tonight. Brilliant. My housemate's boyfriend reckons it's even funnier than Shaun of the Dead - and I think it might be right. One thing I really loved about it is that, despite all the horrific and appalling violence in the film, none of it was gratuitous. I mean, it's a film about horrific and appalling murders, but it's actually got a much lower body count than any of the films it's taking off: sure, all of the bad guys get hurt, but none of them get killed. I really like that. I hate the way most big-budget Hollywood action flicks treat human life as essentially disposable.
Gotta admit, the bit I laughed longest at was the take-off of the line from Chinatown: "Forget it, Nicholas. It's Sanford." Tee-hee!