Kaido challenged the programmers to meet the concept of realistic physics in relation to the movement of the colossi and the subsequent effect this movement would have for Wander, both in terms of how he might be displaced and how he may be able to use this movement to his advantage. For instance, if a colossus were to shake, Kaido wanted Wander's position to shift realistically in response. Additionally, if a colossus' limb was currently horizontal, Kaido wanted the player to be able to run across the limb as though it were any other flat surface. He referred to these two concepts as "player dynamics and reactions" and "organic collision deformation".