Shaun of the Dead (2004)

The benchmark, because it never lets the jokes protect you. Edgar Wright cuts the first half like a slacker comedy, all hangovers and pub plans, so the moment the dead arrive the same quick editing starts working against you. The record-flinging scene is pure slapstick; the siege at the Winchester is genuinely grim, and one death in particular lands harder than most straight zombie films manage. Simon Pegg and Nick Frost play it as a story about friendship first, which is exactly why the scary parts hurt.