Most immersive experience ever
Metro has some of the best graphic engine I've seen in years, IMO even Cryengine couldn't compete with the 4A engine which Metro 2033 uses. The lighting and texture are extremely well done, volumtric lighting and fog effect are also very good, it makes the whole world looks extremely convincing. The sub-surface scattering effect on character's skin makes people looks much more believable, unlike in some other games people tend to looks like plastic dolls.
The story is also it's strong point, since it's adapted from a sci-fi novel, but it has a little twist of it's own while still retains the feel of the novel. I bought the novel after finishing the game, it' will definetly gives you a new perspective on the story.
Combat and AI seems a bit strange and unresponsive at first glance but after I know more about the game, I understand the clumsiness I feel during combat is also part of a story setting. You are not a superhero, you are a survivor in a post apocalyptic world, trying to fighting off monsters and fellow humans while carrying a sort of equipment and ammo, of course you don't move and shoot like a Call of Duty character.
In conclusion, all I can saying is Buy this game, play it, if you learn to appreciate it, this will be one of the most immersive gaming experience you will ever have.