Donkey Kong Country Returns Cheats

Infinite DK Coins
In level 2-2 (Sloppy Sands), there is an area before the checkpoint pig with two squid turrets below a bridge. Using Diddy Kong's jetpack, super bounce from the lower squid to the higher squid shot out from the turrets. After hitting the higher squid just bounce again on the lower squid and rinse and repeat. You can keep repeating this for infinite DK Coins.

3 Extra Lives
Begin playing one of your game saves with a low battery charge on your remote to initiate a message from Cranky; he will warn that your battery is low and award you extra lives to help you out.

Bonus Music Galleries
After you've beaten a boss for a given section of the island, head back to the Extras Menu. You'll have unlocked a bonus music gallery that features the tracks played in the levels of that particular section. It's also worth noting that you must defeat the boss yourself; if you use Super Kong to get past the fight, you won't unlock the music.

Beach Music Gallery: Beat the boss of the Beach section.
Cave Music Gallery: Beat the boss of the Cave section.
Cliff Music Gallery: Beat the boss of the Cliff section.
Factory Music Gallery: Beat the boss of the Factory section.
Forest Music Gallery: Beat the boss of the Forest section.
Jungle Music Gallery: Beat the boss of the Jungle section.
Ruins Music Gallery: Beat the boss of the Ruins section.
Volcano: Beat the boss of the Volcano section.