Save the minimum useful progress

Decide what must persist: an unlocked level, a preference or a completed score. Store a version beside saved data so future changes can detect incompatible formats.

Treat unavailable or malformed storage as a recoverable condition. The game should still start with a safe default and explain any loss of progress clearly.

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.