Croc: Legend of the Gobbos/Crystal Island

This is the fifth, and final island in the game. To reach it you must have collected all the pieces of the puzzle. After defeating Baron Dante and watching the credits, you will start the adventure again from the second secret level of the fourth island, where you can find the last piece of the puzzle. Collect it and you'll be sent to Crystal Island. There are only four levels and one final boss here. Each level corresponds to one of the islands you have previously crossed. The purpose of each level is simply to get to the end of it and to sound the exit gong, but these levels are very challenging.

Levels

 * 5-1 And So The Adventure Returns
 * 5-2 Diet Brrrrr
 * 5-3 Trial on the Isle
 * 5-4 Crox Interactive

Boss Levels
You must beat boss levels to progress to the next level.

Beating a boss level also unlocks a secret level, if you collected all the Gobbos from the levels preceding it.
 * 5-B Secret Sentinel