I haven't played Metro 2033 (though I do mean to!), but I have played Fallout 3 & New Vegas, and I am generally familiar with many different post-apocalyptic settings and scenarios. That in mind, what kind of way is this going to go? Is it going to be 'several hundred years' after a war, or was the war only a few short years ago, or even ending only recently? Is it going to be rad-mutants and zombies, or more marauding gangs, or somewhere in between? 
Just wondering out of curiosity :)