FMP - Research: Donkey Kong Country Character, Level and gameplay design

For my research, I'm going to look into the Donkey Kong Country games for the SNES/GBA.
When these games were released in 1993, 1995 and 1996, they revolutionized the standards for a platformer game, bringing to the table expensive 3D pre-rendered graphics, vibrant immersive worlds, unique gameplay and level mechanics and also sporting an awesome soundtrack.

What I'll be looking into is the design of the game, such as:

.What do the items in the game do, and how do they aid/hinder the player?
.How does the characters moves and playing style change to fit certain situations?
.What unique gimmicks do the levels in these games sport?
.How are character designs molded to fit the characters role/mechanic?
.What trait does these games share with other games designed by Rareware?
.How did the gameplay and mechanics change when the Donkey Kong Country games changed into 3D with Donkey Kong 64 (Nintendo 64) and Donkey Kong Country Returns (Wii)?