The Collector's Lair is the penultimate level of LittleBigPlanet. You can obtain just about every character in the game by rescuing everyone.
If you
The level's icon.
want two extra prizes, at the start you will notice there is a platform to the right of you. You stick the tree sticker on the key switch and the wall will blow up, revealing the prize bubbles.
Walkthrough (Plot)
A sackboy playing the Collector's Lair
Beginning
After you get the two prizes bubbles from the tree sticker, grab onto one of the sponges and you will go downwards. Don't let go until you hit the bottom. Free the bear and his friends, and use the key you received to open the door. The next people that you should release are Little Zim, Big Zam, and Don Lu's Dog. There are also two materials you can get. Next, jump across the shifting platforms, but don't forget to rescue the Crocodile King and Zola.
Freeing the Creator Curators and The Non-Creator Curators
Each Creator Curator and almost every side character except Wobbly Ape, Dumpty, Sheriff Zapata, The Terrible Oni, Fire Breathing Cat, and The Shopkeeper is stuck, and you will need to free them. If you don't free a Creator Curator, you cannot win them as a prize. You will overcome some obstacles during your rescue mission. Make sure you free the people you need for your story levels, too. The last Creator Curators you free (and have to free) are The King and The Queen
4 Player Challenge
If you have 4 Players, don't forget to get the 4 player challenge. It is really simple, all the players have to do is stand on a button until the player on top is at the top and can reach the prize bubbles, one of which is the Audio Object Rainbow Warrior, along with several costume pieces and some other things. It is also actually possible to do this with 3 players.