- Some things are not in harmony with everything else. The flying robots look mismatched and are replaced with armour-clad knights armed with swords or spears. The marks on the girl's right arm are eliminated and her horns are placed on the boy's head. These alterations start a series of changes the team refers to as 'design by subtraction.'

- Ueda asks the animators to make the heroine perform many little actions such as staring at clouds, run after birds or touching her hair.

- He decides to make the boy Japanese and the girl more foreign and Western looking. Their design changes dramatically everyday.

- The armoured knights introduce a new problem. They are so powerful Ico looks too weak. To solve this issue Ueda decides to change them into smokemen. The smokemen's shape allows them to appear from anywhere in the stage, making for some nice surprises.

- With enough puzzles and stages ready, Ueda starts designing the castle. Since he has never visited a castle before he bases his plan on the works of the Italian 17th century artist and architect Giovanni Battista Piranesi.

- The game is half-way complete but Ueda realizes that the PSone is not powerful enough to realize the target. Game development shifts onto PlayStation 2.

- To help with the porting process and give the game a bigger push more people are hired.

- One of the animators, Chika Fukui starts helping Ueda with Yorda's character model.