To get 103% completion here is what to do
1.Beat the game
2.find the lost world by circling those 4 rocks at the world select screen (i forget which way if one way doesen't work go the other way)
3.get all the bonus coins and go to the shack in the lost world now do the levels and get all those bonus coins and return to get the last level
4.return all the cogs from the levels and fight K.Rool in his submarine to get a DK coin
5.if you haven't already, get all the DK coins and go to funky
6,in your new helicopter fly to the top left of the screen to see a giant banana bird traped behind a wall.
7.get all 15 banana birds and go to the wrinkly's save cave now watch the ending
8.you now have 1035completion
To get to the Lost World, the secret final world, use either the jet ski or hovercraft to swim in circles (clockwise) around the four rocks on the world map (it is in the first section on the map, above the first waterfall). Continue going around in these circles until the enterance of the Lost World rises up, leading you to the secret world.
first goto the start board the highlight a game and press l,r,r,l,r,r,l,r,l,r and it will bring up a cheat tab enter water and then go to the left side of funky rentals and touch the waterfall beat the cave and you will get 85 coins
At the select game screen, highlight your game and press L R R L R R L R L R. Then type in one of these codes for the desired effect.
ASAVE - Saves after every level.
COLOR - Makes Dixie purple and Kiddy green.
ERASE - Resets the best time for Riverside Race.
HARDR - Makes the game harder, and if game completed, get 103% completion.
LIVES - Gives you 50 lives.
MERRY - Changes the bonus levels to an x-mas theme.
MUSIC - Music test.
TUFST - Removes all Star Barrels ad DK Barrels, and if completed, get 105% completion.
WATER - When you start, swim to the waterfall on the west of Bazaar's General Store to enter a secret cave, which you can pass a sequence test to get 85 coins.