Great trailer and I will probably get this game sooner or later. I've played Metro 2033 and Metro Last Light and loved both of them. Even though they scared the s... out of me multiple times I couldn't stop playing it. I really like that they provide a bit of a challenge and aren't just the typical gun and run horror/scary games. You actually have to preserve ammunition or you will end up dead really easily. All the Metro video game series know perfectly well how to make this incredibly intense and creepy environment.
Also, I love the crossbow in the trailer, looks badass.