Use simple geometry for a first prototype

Rectangles, circles and lines are enough to establish many movement and collision rules. Their simplicity makes boundaries and feedback easier to inspect.

Add artwork after the rule is playable. Keep a debug view available so decorative sprites do not hide the shape actually used for collision.

Continue the study

Work through a small code example, make one deliberate change and record the effect. The reading links below connect this exercise with animation, input and retro game design.