Note: this is a spoiler-free review.
The inventor of the modern zombie movie has come back, to prove nobody else can do it quite the way he does.
It's arguably true that other horror filmmakers might make their zombies more gross, or more evil, or faster-moving. But all their zombies lack a certain purity of purpose found only in a George Romero zombie.
In Romero's films, zombies are a natural disaster, no more "evil" than a hurricane or an earthquake. They don't want to scare or kill anybody. They do plenty of scaring and killing, make no mistake about it, but that's all accidental. Their one and only goal is to devour the flesh of the living. Their hunger has a terrifying purity, utterly unclouded by malice or apology. They just don't care how much it's going to hurt.
When denied the chance to snack on human flesh, these zombies shamble about in a pale imitation of the life they lived before. Clearly they have some awareness, some residual memory of being alive, making them more human than alien. Their aimless eccentric creepiness when left to themselves somehow renders them far more disturbing than they would be if they spent all their time filled with rage and malice.
Romero never makes the mistake of trying to explain his zombies too much. Even the bit of speculation I've indulged in here is much more than he ever says in his films about why the zombies exist and what their motivations might be. Sometimes his human characters speculate a bit, but he keeps his narratives aloof from all the attempts to understand the zombies, even back in the original Night of the Living Dead when some scientists try to trace the cause of the disaster to radiation from a satellite.
This George doesn't muddle matters with anything like midichlorians to explain why the impossible can happen. He doesn't try to tell us why the dead walk the earth. He just lets them do the voodoo that they do so well.
Land of the Dead is Romero's fourth zombie movie, and in many ways the best of the four. He clearly had a better budget to work with this time around. So we get to watch several excellent well-known actors take on the zombies, including Simon Baker, Dennis Hopper, John Leguizamo and Asia Argento in the major roles. The makeup effects are top-notch, and if there are any digital effects they are so seamless as to be practically invisible, another benefit of a decent budget.