Donkey Kong '94

If a sequel is defined as a game that does more than its predecessor ever could, Donkey Kong '94 for the Game Boy is the greatest sequel of all time. It starts off with the usual four levels of Donkey Kong- the construction site, pie factory, and spring level everyone hated are all present and accounted for. However, once you finish them and expect the game's ending, Donkey Kong steals Pauline again and takes her to 97 more stages of platforming, puzzling fun.

In every level (except those first four, obviously) there's a key and a door. Your job is to bring said key to said door to open it. This is made more difficult by some ingenius puzzle design and a ton of enemies and challenges to get through. Mario has a lot of new moves, too- he can backflip, pick things up, vault himself off ropes, throw and catch hammers, climb vines, and tons of other cool stuff. Nintendo really packs as much into this game as possible, and it shows.