Quote:
2D fighters:
The first: No idea. Street Fighter 1?
The formula: Street Fighter II
The definer: Probably up for debate but for me it's Marvel vs. Capcom 2. I feel it's the standard.
2D platformer:
The first: Pitfall?
The formula: Super Mario Bros.
The definer: Super Mario Bros. 3
AFAIK the first 2D fighter is generally taken to be Karate Champ, whilst the first 2D platformer is Donkey Kong (A few other games had experimented with various elements of it earlier, but DK was the first to put them into the pot that we can now recognize as "2D Platformer").