Modern televisions send data through all sorts of processes before displaying it on the screen. Since the image doesn't appear until that processing is done, it can appear as though the game is running slowly. If your television has an option to turn this processing off, or if it has a "game mode" of some kind, using one of these may help with the issue. Please check your television's support documentation for more details.
Balloon Fight
BUBBLE BOBBLE
Castlevania™
Castlevania II: Simon’s Quest™
Donkey Kong
Donkey Kong Jr.
DOUBLE DRAGON II: THE REVENGE
Dr. Mario
Excitebike
FINAL FANTASY®
Galaga™
GHOSTS 'N GOBLINS™
GRADIUS™
Ice Climber
Kid Icarus
Kirby’s Adventure
Mario Bros.
MEGA MAN™ 2
Metroid
NINJA GAIDEN®
PAC-MAN™
Punch-Out!! Featuring Mr. Dream
StarTropics
SUPER C™
Super Mario Bros.
Super Mario Bros. 2
Super Mario Bros. 3
Tecmo Bowl™
The Legend of Zelda
Zelda II: The Adventure of Link