In the year 2009, we cure cancer.

By 2012, we’re all dead.

That’s the storyline of the new action/horror film I Am Legend, a re-imagining of the 1954 novel by Richard Matheson.

The cure for cancer ends up wiping out most of humanity; most of those who didn’t die mutated into monsters called Dark Seekers who fed on everything alive.

And as far as military scientist Robert Neville (Will Smith) knows, he’s the only uninfected human being left on the planet.

At the very least, he’s the only living person in New York City, where he and his dog, Sam, make the most of their existence while Robert still desperately searches for a cure.

But as the film’s tag line ominously portends, the last man on earth is not alone.

The city is still filled with Dark Seekers, causing Robert to lock down his home when they come out at night.

I’ve always liked Will Smith, and for my money this is absolutely the best work he’s ever done on film. The loneliness of the little routines he establishes for himself just to try to stay sane is heartbreaking, and he plays every scene here to absolute perfection.

In other words, where there’s a Will, there’s a will. And he sells it like a champ.

The first half of the film is especially smart, clever and terrifying. Because even when there’s nothing bad happening, there’s the constant suggestion of danger and doom. It’s really effective.

Unfortunately, whenever the Dark Seekers appear, the movie starts to look and feel like a video game with some of the worst computer effects in a decade.

So you’ve got this amazingly layered, gut-wrenching emotional performance from Will Smith, and a bunch of computer-generated monsters who look like bad rejects from The Mummy Returns.

Come on!

There’s one scene where Robert is doing some tests on a captured Dark Seeker, and it’s just an actress in makeup. And she looks absolutely horrifying.

The action scenes in the latter half of the film would have been far more effective if they’d put some really capable stunt people in really good makeup and let them chase/toss Will Smith around. As it is, almost all of the action scenes involve painfully obvious (and poorly rendered) digital doubles that hop all over the place and take everything away from the gritty realism the film should have aspired to.

Oh, well.

I can’t possibly praise Will Smith’s performance here enough, and a huge nod goes out to Abbey, the three-year-old German Shepherd who plays Sam.

There are moments in the film that will break your heart in half thanks to the excellent work from these two, and the first half is really superb. It’s only when the action ratchets up that the moody, scary atmosphere that had previously been so carefully nurtured devolves into a mess of messy special effects.

I still enjoyed it for what it was. But if they’d put as much time and effort into the monsters as they did into the emotional and psychological stuff, this really would have been a modern classic.

And it’s a shame they don’t give out Oscars for movies like this, because Will Smith deserves one.