What aspect of a game leaves that long lasting impression on you?
When you've finished a game that months/years later still has you thinking about it, what is it about that game that has left you with such fond memories?
Is it the remarkable storytelling?
Is it the gorgeous visuals?
I think for me it has got to be the Soundtrack. Properly orchestrated music can take a scenario in game and breathe emotion into it. And for me, the ability to download the song/soundtrack that put me in such an emotional state during the game and listen to it anywhere I want, allows me to relive those moments even if I'm miles away from my game console.