Metro 2033 (video game)/WMG

The mushrooms the Metro inhabitants are growing are really magic shrooms
The Metro has just a few hundred inhabitants (because it couldn't sustain more due to lack of space and light to grow enough crops), all the adventures in Metro are just the hallucinations of Artjom. All Metro inhabitants sit around all day in an empty, completely non-mystical metro station, they sometimes go into the (completely non monster-infested) tunnels to foster their mushrooms when they are more sober. Not all of the mushrooms are "magic", of course, most are simply champinions. Artjom ist just having a bad trip.

Oh, and the pigs don't exist either. Feeding farm animals when supplies are low anyway? Not a chance.