Donkey Kong Returns 3D

For collecting all K-O-N-G letters in a level you will receive a red medal. If you collect all these letters again in mirror mode, the medal will turn from red into blue.

To unlock the pictures labeled "only the most determined ape may unlock this item," collect every KONG letter in Mirror Mode, complete every stage in Mirror Mode, and get all the Puzzle pieces.

There's a special temple stage hidden within each section of map. In order to find them, you have to collect the K-O-N-G letters from every level of that particular map section.

Once you've gotten inside the Golden Temple, you'll unlock a new section on the map called the Cloud. Complete all nine of its levels to unlock Mirror Mode. This mode allows you to play through flipped versions of each level. In addition, Diddy Kong is not available, and you're only given one heart.

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.