Two-player mode (PAL and Japanese NTSC versions)
Finish the game and wait for the credits to end. Once you regain control of Ico, look for Yorda near the seashore. A save prompt will appear after the final ending. Save the game and restart to have Yorda playable using controller two and new music.
Finish the game once, then start another game. Follow the steps to where you got the Mace in the first time, and this time you will get a lightsaber that kills Smoke Creatures in one hit .You must be holding Yorda's hand to activate it.
Extra puzzle (PAL version)
An extra puzzle has been added in the room that leads to the top of the waterfall garden in the PAL version of the game. Whereas before you could shimmy around the room on bars, now you can only reach a switch. Pull this to start a giant wooden piston in the room. To get to the window, stand on the piston and press Jump just as it begins to sink...
How to avoid losing Yorda
To avoid losing Yorda, as soon as you set her free press R1 and hold her hand, then run to the door . You should also pick up the stick that falls so you can defeat the Shadow Creatures easily.
How to defeat the Smoke Creatures easily
When you enter a room, and it is a clear run to the portal on the other side, take Yorda by the hand and run her to the portal with the black Smoke Creatures chasing you. As you get close to the portal, Yorda's activation of the portal will create lightning which will destroy the creatures anywhere near you.
How to find Yorda
When in the last level with Ico's horns cut off on the beach, go towards the left following the shore of the beach to find Yorda.
When turning big wheels, as when shutting off the water, turn from the farthest point to go faster.