The plot needs no explanation, as you've seen it a million times. But the screenwriters have such fun tweaking all the signposts that you can't help but giggle at it all. They also continually go for laughs amid the carnage and mayhem, and for the most part it works. The silly story isn't remotely coherent, but you can't exactly criticise a film like this for being illogical, can you? The actors give their all, running, screaming, shooting and stomping like mad, without a moment of wink-wink parody, which makes it all the more effective as a spoof along the lines of Mars Attacks. What the film lacks in directoral skill (it seems a bit flat and timid) is more than made up for in post-production; the special effects are absolutely fantastic ... and startlingly realistic! This is not a film for someone suffering from arachnophobia. Unless of course they go see the film with someone they want to squeeze the life out of.