Metro: Last Light Redux

This is story related and can't be missed. You'll unlock this during the Sparta mission. However, you'll want to make sure you get some optional moral points during this mission to work toward the Redemption achievement, as well as the musical instruments if you're on the 360 version for that achievement that didn't carry over to the Xbox One version. Check out the video below for a full playthrough of the game showing all collectibles and the Moral Points I obtained (I skipped a lot of them) in order to get the Redemption achievement. Sparta starts at timestamp 00:14.