4. Metroid
One of the earliest NES games I ever played and also one of the most satisfying. The dark foreboding intro music with a glimmer of... what is that, hope at the end? Really put me in the mood... to slay alien creatures!
I loved how the game just drops you on a planet and lets you explore freely. You'll see so many places you can't quite reach or get to, only to find the awesome power up later that lets you explore further. Masterful platforming and boss battles (eww, look how gross Mother Brain looks!) add to this masterful game... masterful! Also, Samus is a chick and she likes to wear a bikini under that robot looking suit of hers!
A fantastic start to a fantastic franchise!