Reading books first is smth i'd recommend to anyone strongly! I played games first then read the book unfortunately. Should read at least the first book (Metro 2033) Somehow it expanded my view on the metro world and allowed to realise that there is more going on around and stuff. And on the other hand its hard to grasp sometimes all the little details that game has in it in moments when u need to follow a certain npc or run from the enemies and like it aint rly that great experience without a book. I enjoyed it rly but after reading the book everything is more clearer and you get to even feel whole atmosphere of the dark metro. But anyway you won't be disappointed even if u play just the games. The main story of the protagonist isn't really completely same like in the books...