In 1994 Nintendo released a sequal to the first Donkey Kong game. This version contains multiple worlds, each with around 4-6 ordinary courses plus two boss courses. The first levels are identical to the ones in the original but after you've defeated Donkey Kong the first time a whole new game opens up. The following levels are more complicated than the first ones.
In each level Mario must find a key to open the door to be able to proceed to the next course. Scattered around the levels are also various gifts for Pauline, like hats and jewellery. If you find those you get additional points.
On every 4:th level you meet up with the big ol' monkey himself. Mario has also learned some new moves like a special "high jump".

Mario rescuse Pauline in the first city.
 

The first world