When the level begins, walk to the left and enter the mine to reach a bonus area. Jump up onto moving platforms to collect a couple coins and lots of bananas. Once you have cleared the area, you get a Puzzle Piece.
In order to get the second Puzzle Piece, collect all of the bananas in the wavy line. The K KONG letter is in this line. The banana right after the K is tough, since you have to drop down a bit to get it.
The K KONG letter is easy to get, especially if you are going after the bananas to grab the Puzzle Piece. Just be careful not to hit the pointed rock that hangs down from the ceiling right before this letter.
Carefully fly through jagged rocks that stick up from the ground, and then dive down a bit to get the O KONG letter. You must pull up quickly so you don’t crash into another rock.
Right after you fly past the checkpoint, carefully collect all six bananas that form a wavy line. You will be rewarded with another Puzzle Piece.
As the mine train goes through a series of corkscrew loops, it will drop off four Mole Guards hanging from balloons. Fly over the Mole Guards and run into their balloons to pop them and cause the Mole Guards to fall. Hit all four of the balloons and a Puzzle Piece will appear for you to pick up.
Right after you reach the end of the corkscrew track, drive down to get the N KONG letter. Be ready to pull up quickly.
After exiting a cave, you now have to deal with crystals that drop down from the ceiling. Stay up high and carefully avoid the jagged pieces of crystal as you get the G KONG letter. After retrieving the letter, get back down a bit and proceed to the Slot-Machine Barrel.
Don’t hit the Slot-Machine Barrel right away. Instead, go past it and pound the cactus to get the last Puzzle Piece. Now hit the Slot-Machine Barrel to complete the level.