In-game, Donkey Kong can jump on Rambi to ride him. While riding Rambi, the player can usually hit enemies they run into, and even kill critters they usually cannot kill otherwise. Furthermore, Rambi's horn allows the player to break past certain walls and find bonus rooms or secrets. Since Donkey Kong Country 2, Rambi is also able to charge by holding a button, and then ramming a high speed into enemies or walls to uncover secrets.
In Super Smash Flash 2
Upon arrival, Rambi will start running across the stage, sometimes jumping. If he runs into opponents, they will get hit, with low damage but decent knockback. Rambi's back acts as a platform that players can jump into, and Rambi can carry them across the stage.