Donkey Kong Country 2 addressed all of the problems of the original, and turned out to be the best in the trilogy.
The game starts off where the last one ended, on K. Rool's pirate ship. But this time, instead of banana's, K. Rool has stolen DK! Oh no! It's up to Diddy to save him, and his girlfriend, Dixie Kong, is up for the adventure too. Dixie is a nice addition to the game, and she remains the most unique in the series. She has a long pony tail which somehow helps here fly through the air. She can also wake baddies with it. The gameplay is the same as the original, but improved. As mentioned earlier, the idea of two characters at once is used to the potential it should have in the original. This means solid platforming with some small puzzle elements. How do you get to that barrel? Just throw Dixie up there! It adds great fun and works well. One move was taking out though, the ability to pound the ground and find hidden treasures like bananas or coins. It's not really a big deal, and it was never really that fun in the original anyway.
The graphics and sound are of the same amazing quality they were the first time around. Everything looks and sounds perfect, and you will love the character sprites and background designs. DKC 2 is a very challenging game, and some of the bosses can drive you crazy. The levels are really hard too, and it should take you a good time to beat the game. There are also lots of hidden things like DK coins, and a hidden world too.
I think Donkey Kong Country 2: Diddy's Kong Quest is the perfect game for platforming afficianados. Most anyone else would find a good game here too. The difficulty may turn some off, but overall its a top notch game superior to the original, albeit in small ways.