Compared to "Metro 2033" original there were of course many improvements, from its visual context to the audio and even the possibility provided for a better orientation and gun disposal. The storyline in these games is so good and it is shown through the climate and backgrounds seen and heard in this game: the sinister dark sky and the misery left behind in this apocalyptic scenario, big scary creatures who now rule the outside world, the nostalgia left behind in the people who want to leave the metro and live again their lives as they did before. Loved the sneaky challenges, it added a great sense of realism, since all factors counted (light from the candles, sounds and shadows). I liked the variety of weapons, due to the fact that they didn't provide many but for the times one could go and buy more on the shops. I also liked the possibility to replace them with the weapons from the people killed or from the already corpses found on the ground, something which the original game didn't allow.
Some flaws in the game: the weird fake voice acting from the children in it; The almost impossibility to kill a beast with head shots.
Overall I really liked this game, the difficult and sneaky challenges it provides, the good story and the awesome environment featured.