I traded in some games for a pre-owned copy of Metro 2033 earlier in the week. I lasted 20 minutes on it. The atmosphere and premise are interesting but the first person viewpoint was jerky, cheap and nasty, the gunplay was about as interesting as watching paint dry. There was absolutely no excitement in rattling off a load of rounds at mutants.
I returned it the next day and claimed it was present for someone who turned out to own it already. I've now got money on a Game trade-in card in anticipation of the new Medal of Honor next week.