Iterations
V0
The game had a “pause state” for players to edit forces, and a “move state” where objects resumed motion and the forces added by players were truly applied. Players had to switch between states using the two buttons on both sides of the screen.
Problem
As discussed, the time lag between “adding a force” and “seeing the effect” made it hard for players to observe the causal relationships, and switching between move/pause states caused more extraneous cognitive load.
Solution
Removed the “pause state” and added a “controller button”, through which players add real-time forces.
V1.0
The first level at this point introduced both forces and constant velocity. Players learned how to add forces and cancel forces, and had to pass through the “constant velocity gate” to finish this level.
Problem
The quest did not feel natural -- “Why do I have to pass through the gate?”. The behavior needed a reason.
Solution
Added a flag inside the gate. It creates the reason for players to pass through the gate.
V1.1
Problem
It lacked a clear representation of the object’s velocity.
My original idea of using the dotted trajectory line to visualize velocity failed. The relevance between the length of trajectory line segments and the object’s speed was not direct enough for players to make intuitive sense. The trajectory line was ignored or treated as part of the background.
Solution
Added a “speed bar” that shows the object’s speed, and a “direction pointer” that shows the object’s moving direction.
V1.2
Problem
Too many things taught at the same time. As discussed, to avoid overwhelming the players, adding forces and canceling forces (and the idea of constant velocity) should be introduced one at a time.
Problem
The new added tiny square got lost quite easily. And then the player was stuck.
Problem
As discussed, the representation of velocity using a speed bar and a direction pointer contradicts with the learning goal of “thinking with vectors”.
Solution
The first level was separated into two. The goal for first level changed to chasing a tiny square. Doing so gives players more opportunities to observe how forces affect motion and get used to the control.
Solution
Teleport the tiny square every time it gets outside the camera view.
Solution
The two components were replaced with a single velocity vector--the line attached to the moving square.