Actually most locations directly struck by a nuclear weapon will become impressive grass-and-woods covered craters in very short order, plants have incredible radiation resistance. The largest logical fallacy of 'post apocalyptic' depictions is the blasted wasteland. That's just not how nature responds to major events, take a look at volcanoes, wildfires, and any other landscape-changing event. The addition of radiation to the mix is almost meaningless to nature, it simply adapts, and rather impressively cleans fallout in very short order (especially water systems, the only real contamination threat to a water system is ground water, the rest just gets buried in the sediment on the bottom of the ocean). You just aren't going to find a 'realistic' nuclear war game, because the reality is completely divorced from popular media.
Well, not necessarily. Yes, not all plants on earth would die, but trees that receive a high dose of radiation will die.
http://en.wikipedia.org/wiki/Red_ForestHowever, this is not an impediment to new trees growing. As the article notes, biodiversity has actually increased in the area of the "Red Forest", even though some of the plants are stunted and the animals have had some minor issues as well.
Oh, hey, how about the Metro games? I understand they have a little bit of giant radioactive monster silliness, but are mostly grimdark struggle to survive and avoid radiation kinds of games.
The Metro games are all bullshit because the most of Metro in Moscow is under the ground water level and there are pumps working constantly to avoid it getting flooded.
I think it's handwaved as the pumps are still working, except in the parts of the Metro where they've broken down and they've flooded. If you've read the books, it makes a lot more sense because Metro 2034 actually ends with one of the stations flooding. It's just not really mentioned in the games. If you get a chance, read the books, they're way better than the games.
Also, the monsters make more sense in the books. They're more... Ephemeral? More shadows in the dark, and bloated rumours than actual giant irradiated beasts. Again, the games are worse in this regard, but it makes sense why. I can count the numbers of times Artyom fires his gun in the book on the fingers of my hands. Half of those are him just shooting into the darkness in panic. The games are a totally different story, for the necessity of making it an FPS.