All of these should be essentials:
Ninja Gaiden
Super Mario Bros. 3
The Legend of Zelda
Megaman 2
Megaman 3
The Legend of Zelda 2: The Adventure of Link
Contra
Super C
Metroid
Mike Tyson's Punch-Out!!
Battletoads
Battletoads Double Dragon
Bionic Commando
Kid Icarus
Startropics 1
Castlevania 1-3...