Well it's the ds edition right..?
Level 3-4: the pirate ship
To get out of there you must enter in the locked door in the middle of the ship. Once you're in, you'll find another locked door. So the first step is find those keys right..? ok..
To find the first one enter in the second pipe in the ship, counting from the right. Once in you'll find a door below, where you must enter, to do that push with the tongue the jumping enemies.
You must go below again until find a new door, this one will lead you to the zone where the key lurks. Go to the right, there you can go up with the jar (smack it with an egg to climb it). Upstairs it's the key close a door. In the next zone, go up to leave with a pipe and you'll be again in the ship's deck. Open the locked door in the middle. Now return to the deck and enter in the second door (counting from the left). Now go left, where you can go down and enter in a new door. Now where you appear, move the box at your right a little to the left to go up. There will be a jar, hit it with an egg to make an key appear. Then go down and follow the path at your right, down you'll find a door. Here you'll see an elastic ball.
Use it to be at the top of everything and get out of this zone. In the new zone go up by the only possible way and you'll find a ring, then you can get out with the pipe upstairs. You'll return to the deck. Enter to the past locked door and follow the only way down (the way you go down the darkest it going to be but at the end of the path will be an locked door). Once there you will face the final boss..!! FINALLY
You got to jump in the platforms, it's water everywhere.
To defeat it you have to wait it jumps and shoot it with an egg, if you have no more, defeat the enemies to acquire more.. LUCK..!